Rivers of Time is a 1993 collection of short stories by science fiction

Science fiction

Science fiction is a genre of fiction dealing with imaginary but more or less plausible content such as future settings, futuristic science and technology, space travel, aliens, and paranormal abilities...

 and fantasy

Fantasy

Fantasy is a genre of fiction that commonly uses magic and other supernatural phenomena as a primary element of plot, theme, or setting. Many works within the genre take place in imaginary worlds where magic is common...

 author L. Sprague de Camp

L. Sprague de Camp

Lyon Sprague de Camp was an American author of science fiction and fantasy books, non-fiction and biography. In a writing career spanning 60 years, he wrote over 100 books, including novels and notable works of non-fiction, including biographies of other important fantasy authors...

, first published in paperback by Baen Books

Baen Books

Baen Books is an American publishing company established in 1983 by long time science fiction publisher and editor Jim Baen. It is a science fiction and fantasy publishing house that emphasizes space opera, hard science fiction, military science fiction, and fantasy...

. All but two of the pieces were originally published between 1956 and 1993 in the magazines Galaxy

Galaxy Science Fiction

Galaxy Science Fiction was an American digest-size science fiction magazine, published from 1950 to 1980. It was founded by an Italian company, World Editions, which was looking to break in to the American market. World Editions hired as editor H. L...

, The Magazine of Fantasy & Science Fiction

The Magazine of Fantasy & Science Fiction

The Magazine of Fantasy & Science Fiction is a digest-size American fantasy and science fiction magazine first published in 1949 by Mystery House and then by Fantasy House. Both were subsidiaries of Lawrence Spivak's Mercury Publications, which took over as publisher in 1958. Spilogale, Inc...

, Analog, and Asimov's Science Fiction

Asimov's Science Fiction

Asimov's Science Fiction is an American science fiction magazine which publishes science fiction and fantasy and perpetuates the name of author and biochemist Isaac Asimov...

, and the Robert Silverberg

Robert Silverberg

Robert Silverberg is an American author, best known for writing science fiction. He is a multiple nominee of the Hugo Award and a winner of the Nebula Award.-Early years:...

-edited anthology The Ultimate Dinosaur. The remaining pieces were first published in the present work.

The book collects the author's nine tales of time-traveling hunter Reginald Rivers, the hero of his 1956 classic, "A Gun for Dinosaur

A Gun for Dinosaur

"A Gun for Dinosaur" is a science fiction story written by L. Sprague de Camp as part of his Rivers of Time series. It was first published in the magazine Galaxy Science Fiction for March, 1956, and first appeared in book form in the anthology The World That Couldn't Be and 8 Other SF Novelets...

". He wrote another Rivers story in 1990 to fulfil a request by Robert Silverberg for a dinosaur story for his 1991 anthology The Ultimate Dinosaur; afterwards, de Camp added to the sequence until he had enough stories for a book.

Contents

• "Faunas" (poem)
• "A Gun for Dinosaur
  A Gun for Dinosaur
  "A Gun for Dinosaur" is a science fiction story written by L. Sprague de Camp as part of his Rivers of Time series. It was first published in the magazine Galaxy Science Fiction for March, 1956, and first appeared in book form in the anthology The World That Couldn't Be and 8 Other SF Novelets...
  
  " - Rivers explains to a client the reason for his policy of only taking clients able to handle a heavy-duty gun back to the late Mesozoic, with a hair-raising narrative of what once happened to a client who couldn't.
• "The Cayuse" - Reggie tells the story of the only time they tried to bring a manned vehicle back to the prehistoric days, in which the gas fumes acted like a mating scent for a Parasaurolophus, leading it to try to mate with the car, leading to its subsequent destruction in the river.
• "Crocamander Quest" - Misadventures bedevil a trip to the age of Amphibians.
• "Miocene Romance" - An animal rights activist tries to go on a hunt to prevent anyone from shooting the extinct animals. When she is denied, she stows away. As the hunt goes on, the elder of the two sahibs kills animals just so he can say he has to his friends, and even kills an entire herd of gomphotheres.
• "The Synthetic Barbarian" - A client whose motive for financing a time expedition proves to be personal wish-fulfillment gets more than he bargained for.
• "The Satanic Illusion" - A challenge from religious fundamentalists to prove the theory of evolution through a time travel expedition serves instead to demonstrate the infinite capacity of the human mind for self-delusion, even if it has to involve murder.
• "The Big Splash" - An expedition to chronicle the K-T event and resolve rival theories about its cause nearly makes the time-travelers participants in the great extinction.
• "The Mislaid Mastodon" - A "bring-'em-back alive" expedition to retrieve a mastodon from the past to the present goes disastrously awry.
• "The Honeymoon Dragon" - Rivers and his wife visit his native Australia, where they themselves become guest on another time safari operation. The trip proves more dangerous than they expect when a fellow time-traveler with an inexplicable grudge against Rivers turns the expedition into a deadly trap.
• "Afterword" - A brief resume from the author on how the stories in the book came to be written.

The series

The Rivers stories take the form of first-person narratives by the protagonist told to companions whose identities vary, but who have in common the fact that their contributions to the conversation are omitted, and must be inferred from those of Rivers. Every story is an anecdote from Rivers' career as a conductor of time safaris to previous eras, both to hunt prehistoric creatures and for scientific purposes (and, occasionally, anti-scientific purposes). In addition to Rivers, the main recurring characters include fellow members of his safari firm, including his partner Chandra Aiyar, camp boss Beauregard Black, and cook Ming. In most instances, the actions of their human clients prove more troublesome than those of the extinct fauna, a theme set in "Faunas", a 1968 poem by de Camp that precedes the stories. An afterword by the author tells how he came to write the series.

Rules of time travel

1. The effective range of the stories' time machine is from about one hundred thousand years to about one billion years in the past, with periods more recent or earlier beyond its ability to reach.
2. The further back in time the machine travels the less accurate it is; beyond the Triassic, it may arrive days or even months off schedule.
3. The amount of time the machine spends in another era appears to equal in length to the amount of time that elapses in the present, in its absence.
4. The timestream does not appear to allow paradox, defined as anything that might significantly alter events subsequent to the period visited. For instance, a person cannot travel to the same time twice. Attempting to do results in one being thrown back to the present, "torn to shreds in the process." The same would presumably result from attempting to interact with early humans. Therefore the time machine is restricted from visiting the period of protohuman development, and refrains from visiting any time within one thousand years of a previous visit.

Species featured

Prehistoric species of various eras featured in the series include
Agriochoerus

Agriochoerus

Agriochoerus is an extinct genus of terrestrial herbivore of the family Agriochoeridae, endemic to North America. Agriochoerus and other agriochoerids possessed claws, which is rare within Artiodactyla....

,
Alamosaurus

Alamosaurus

Alamosaurus is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now North America. It was a large quadrupedal herbivore. Isolated vertebrae and limb bones indicate that it reached sizes comparable to Argentinosaurus and Puertasaurus, which would make it the...

,
Archaeotherium

Archaeotherium

Archaeotherium is an extinct artiodactyl genus of the family Entelodontidae, endemic to North America during the Oligocene epoch , existing for approximately . Archaeotherium was about 1.2m tall at the shoulder and around 2m long and weighing around 270kg.It was a relative of javelinas and pigs...

,
Brontops

Brontops

Brontops is an extinct genus of rhinoceros-like perissodactyl mammal.According to one source, Brontops is subsumed into genus Megacerops.-Appearance:...

,
Camptosaurus

Camptosaurus

Camptosaurus is a genus of plant-eating, beaked ornithischian dinosaurs of the Late Jurassic period of western North America. The name means 'flexible lizard', ....

,
Columbian Mammoth

Columbian Mammoth

The Columbian Mammoth is an extinct species of elephant of the Quaternary period that appeared in North America during the late Pleistocene. It is believed by some authorities to be the same species as its slightly larger cousin, M...

,
Coryphodon

Coryphodon

Coryphodon is an extinct genus of mammal. It was widespread in North America between 59 and 51 million years ago. It is regarded as the ancestor of the genus Hypercoryphodon of Mid Eocene Mongolia....

,
Deinosuchus

Deinosuchus

Deinosuchus is an extinct genus related to the alligator that lived 73 to 80 Ma , during the late Cretaceous period. The name translates as "terrible crocodile" and is derived from the Greek deinos , "terrible", and soukhos , "crocodile"...

,
Diprotodon

Diprotodon

Diprotodon, meaning "two forward teeth", sometimes known as the Giant Wombat or the Rhinoceros Wombat, was the largest known marsupial that ever lived...

,
Eurypterid

Eurypterid

Eurypterids are an extinct group of arthropods related to arachnids which include the largest known arthropods that ever lived. They are members of the extinct order Eurypterida ; which is the most diverse Paleozoic chelicerate order in terms of species...

,
Gastornis

Gastornis

Gastornis is an extinct genus of large flightless bird that lived during the late Paleocene and Eocene epochs of the Cenozoic. It was named in 1855, after Gaston Planté, who had discovered the first fossils in Argile Plastique formation deposits at Meudon near Paris...

(called Diatryma),
Gorgosaurus

Gorgosaurus

Gorgosaurus is a genus of tyrannosaurid theropod dinosaur that lived in western North America during the Late Cretaceous Period, between about 76.5 and 75 million years ago. Fossil remains have been found in the Canadian province of Alberta and possibly the U.S. state of Montana....

,
Hoplophoneus

Hoplophoneus

Hoplophoneus is an extinct genus of the family Nimravidae, subfamily Nimravinae endemic to North America during the Late Eocene-Oligocene epochs , existing for approximately .-Taxonomy:...

,
Hyaenodon

Hyaenodon

Hyaenodon is an extinct genus of Hyaenodonts, a group of carnivorous creodonts of the family Hyaenodontidae endemic to all continents except South America, Australia and Antarctica, living from 42—15.9 mya, existing for approximately .-Morphology:Some species of this genus were amongst the largest...

,
Ichthyostega

Ichthyostega

Ichthyostega is an early tetrapod genus that lived at the end of the Upper Devonian period . It was a labyrinthodont, one of the first fossil record of tetrapods. Ichthyostega possessed lungs and limbs that helped it navigate through shallow water in swamps...

,
Mastodon

Mastodon

Mastodons were large tusked mammal species of the extinct genus Mammut which inhabited Asia, Africa, Europe, North America and Central America from the Oligocene through Pleistocene, 33.9 mya to 11,000 years ago. The American mastodon is the most recent and best known species of the group...

,
Megalania

Megalania

Megalania is a giant extinct goanna or monitor lizard. It was part of a megafaunal assemblage that inhabited southern Australia during the Pleistocene, and appears to have disappeared around 40,000 years ago...

,
Merycoidodon

Merycoidodon

Merycoidodon is an extinct genus of terrestrial herbivore of the family Merycoidodontidae, subfamily Merycoidodontinae ,...

,
Metamynodon

Metamynodon

Metamynodon is an extinct genus of amynodont perissodactyls, and is among the longest lived genera of amynodonts, having first appeared during the late Eocene, and becoming extinct during the early Miocene, when it was supplanted by the semiaquatic rhinoceros, Teleoceras...

,
Metoposaurus

Metoposaurus

Metoposaurus is an extinct genus of temnospondyl amphibian, known from the Late Triassic of Europe. This mostly aquatic animal possessed small, weak limbs, had sharp teeth and a large flat head. The main diet of this highly flattened creature was fish which it captured with its wide jaws lined with...

,
Mylodon

Mylodon

Mylodon is an extinct genus of giant ground sloth that lived in the Patagonia area of South America until roughly 10,000 years ago.Mylodon weighed about and stood up to tall when raised up on its hind legs. Preserved dung has shown it was a herbivore. It had very thick hide and had osteoderms...

,
Ornithomimus

Ornithomimus

Ornithomimus is a genus of ornithomimid dinosaur from the Late Cretaceous Period of what is now North America.In 1890 Ornithomimus velox was named by Othniel Charles Marsh on the basis of a foot and partial hand from the Maastrichtian Denver Formation. Another seventeen species have been named since...

,
Parasaurolophus

Parasaurolophus

Parasaurolophus is a genus of ornithopod dinosaur that lived in what is now North America during the Late Cretaceous Period, about 76.5–73 million years ago. It was an herbivore that walked both as a biped and a quadruped. Three species are recognized: P. walkeri , P. tubicen, and the...

,
Phenacodus

Phenacodus

Phenacodus is an extinct genus of mammals from the late Paleocene through middle Eocene, about 55 million years ago. It is one of the earliest and most primitive of the ungulate mammals, typifying the family Phenacodontidae and the order Condylarthra....

,
Placerias

Placerias

Placerias was a dicynodont that lived during the late Carnian age of the Triassic Period...

,
Postosuchus

Postosuchus

Postosuchus, meaning "crocodile from Post ", was a basal archosaur that lived in what is now North America during the middle through to the late Triassic period...

,
Procoptodon

Procoptodon

Procoptodon was a genus of giant short-faced kangaroo living in Australia during the Pleistocene epoch. P. goliah, the largest known kangaroo that ever existed, stood approximately 2 meters tall. They weighed about ....

,
Rutiodon

Rutiodon

Rutiodon is an extinct genus of archosaur belonging to the family Phytosauridae. It lived during the Late Triassic period, and was about 10 to 25 feet in length...

,
Saurophaganax

Saurophaganax

Saurophaganax is a genus of allosaurid dinosaur from the Morrison Formation of Late Jurassic Oklahoma . Some paleontologists consider it to be a species of Allosaurus...

or Allosaurus

Allosaurus

Allosaurus is a genus of large theropod dinosaur that lived 155 to 150 million years ago during the late Jurassic period . The name Allosaurus means "different lizard". It is derived from the Greek /allos and /sauros...

(referred to as Epanterias

Epanterias

Epanterias is a dubious genus of theropod dinosaur from the Kimmeridgian-Tithonian-age Upper Jurassic upper Morrison Formation of Garden Park, Colorado. It was described by Edward Drinker Cope in 1878. The type species is Epanterias amplexus. This genus is based on what is now AMNH 5767, parts of...

),
Stegosaurus

Stegosaurus

Stegosaurus is a genus of armored stegosaurid dinosaur. They lived during the Late Jurassic period , some 155 to 150 million years ago in what is now western North America. In 2006, a specimen of Stegosaurus was announced from Portugal, showing that they were present in Europe as well...

,
Teratosaurus

Teratosaurus

Teratosaurus was a genus of rauisuchian known from the Triassic Stubensandstein of Germany...

,
Triceratops

Triceratops

Triceratops is a genus of herbivorous ceratopsid dinosaur which lived during the late Maastrichtian stage of the Late Cretaceous Period, around 68 to 65 million years ago in what is now North America. It was one of the last dinosaur genera to appear before the great Cretaceous–Paleogene...

,
Troodon formosus (presented as Stenonychosaurus, and supposedly a type of pachycephalosaur), and
Tyrannosaurus

Tyrannosaurus

Tyrannosaurus meaning "tyrant," and sauros meaning "lizard") is a genus of coelurosaurian theropod dinosaur. The species Tyrannosaurus rex , commonly abbreviated to T. rex, is a fixture in popular culture. It lived throughout what is now western North America, with a much wider range than other...

 trionychus.

Tyrannosaurs of the species Gorgosaurus

Gorgosaurus

Gorgosaurus is a genus of tyrannosaurid theropod dinosaur that lived in western North America during the Late Cretaceous Period, between about 76.5 and 75 million years ago. Fossil remains have been found in the Canadian province of Alberta and possibly the U.S. state of Montana....

 are mentioned occasionally, and many times Reginald Rivers will say that the Raja is out in some period in the Cenozoic, taking a group to hunt some form of prehistoric mammal such as titanothere, entelodont

Entelodont

Entelodonts, sometimes nicknamed hell pigs or terminator pigs, is an extinct family of pig-like omnivores endemic to forests and plains of North America, Europe, and Asia from the middle Eocene to early Miocene epochs , existing for approximately .-Taxonomy:Entelodontidae was named by Richard...

, or uintathere. Prehistoric marsupials and Indricotherium are mentioned in "The Synthetic Barbarian," and numerous Pleistocene Megafauna are seen in "The Mislaid Mastodon," including Casteroides ohioensis and the American Lion

American lion

The American lion — also known as the North American lion, Naegele’s giant jaguar or American cave lion — is an extinct lion of the family Felidae, endemic to North America during the Pleistocene epoch , existing for approximately...

.

Obsolete science

While Rivers of Time is a well researched time travel series, paleontological knowledge has improved since the stories were written, rendering some aspects of its portrait of the prehistoric past obsolete. Dated material includes the following:

• Alamosaurus and other sauropods, portrayed as aquatic creatures forced to stay in the water much of the time, are now recognized as fully land-dwelling.
• Stenonychosaurus, portrayed as a pachycephalosaurid, is no longer recognized as a valid species, having been found to be identical to the Troodon, a raptor-like theropod.
• Gorgosaurus, portrayed as a type of carnosaur distinct from tyrannosaurs, is now included in the tyrannosaur genus.
• Tyrannosaurus and other fauna portrayed as living in the middle Cretaceous in fact appeared in the last five to seven million years of the period; the actual fauna of the middle Cretaceous included species such as Nothronychus
  Nothronychus
  Nothronychus is a genus of theropod dinosaur classified in the group Therizinosauria, from the Cretaceous of North America.The type species of this dinosaur, Nothronychus mckinleyi, was described by James Kirkland and Douglas G. Wolfe in 2001...
  
  , Pawpawsaurus
  Pawpawsaurus
  Pawpawsaurus, meaning "Pawpaw Lizard", is a nodosaurid ankylosaur from the Cretaceous of Tarrant County, Texas, discovered in May 1992. The only species yet assigned to this taxon, Pawpawsaurus campbelli, is based on a complete skull from the marine Paw Paw Formation...
  
  , Protohadros
  Protohadros
  Protohadros is a genus of herbivorous ornithischian dinosaur from the Late Cretaceous , 95 million years ago....
  
  , and Zuniceratops
  Zuniceratops
  Zuniceratops was a ceratopsian dinosaur from the mid Turonian of the Late Cretaceous Period of what is now New Mexico, United States...
  
  .
• The teratosaur of the late Triassic period is portrayed as a carnosaur; current thinking suggests that it and most other "carnosaurs" of the time were actually rauisuchians (with the exceptions of Liliensternus
  Liliensternus
  Liliensternus was a genus of coelophysoid dinosaur from the Late Triassic period, about 205 Ma.Liliensternus was originally named in 1934 by Friedrich von Huene as a second species of Halticosaurus, H. liliensterni, the specific name honouring the German amateur paleontologist, Dr...
  
  , Dilophosaurus
  Dilophosaurus
  Dilophosaurus was a theropod dinosaur from the Sinemurian stage of the Early Jurassic Period, about 193 million years ago. The first specimens were described in 1954, but it was not until over a decade later that the genus received its current name...
  
  , and their kin).

Sequel

A tenth story of Reginald Rivers, "Gun, Not for Dinosaur", authored by Chris Bunch

Chris Bunch

Christopher R. "Chris" Bunch was an American science fiction, fantasy and television writer, who wrote and co-wrote about thirty novels....

, appeared in Harry Turtledove

Harry Turtledove

Harry Norman Turtledove is an American novelist, who has produced works in several genres including alternate history, historical fiction, fantasy and science fiction.- Life :...

's 2005 tribute anthology honoring L. Sprague de Camp, The Enchanter Completed

The Enchanter Completed: A Tribute Anthology for L. Sprague de Camp

The Enchanter Completed: A Tribute Anthology for L. Sprague de Camp is a 2005 gedenkschrift honoring science fiction and fantasy author L. Sprague de Camp, in the form of an anthology of short stories edited by Harry Turtledove. It was first published in paperback by Baen Books...

.