The Case for Mars: The Plan to Settle the Red Planet and Why We Must is a nonfiction science book by Robert Zubrin

Robert Zubrin

Robert Zubrin is an American aerospace engineer and author, best known for his advocacy of the manned exploration of Mars. He was the driving force behind Mars Direct—a proposal intended to produce significant reductions in the cost and complexity of such a mission...

, first published in 1996.

The book details Zubrin's Mars Direct

Mars Direct

Mars Direct is a proposal for a manned mission to Mars. Proponents of the scheme have claimed it to be both cost-effective and that it can be conducted with current technology. It was originally detailed in a research paper by NASA engineers Robert Zubrin and David Baker in 1990, and later expanded...

 plan to make the first human landing on Mars

Mars

Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

. The plan focuses on keeping costs down by making use of automated systems and available materials on Mars to manufacture the return journey's fuel in situ

In situ

In situ is a Latin phrase which translated literally as 'In position'. It is used in many different contexts.-Aerospace:In the aerospace industry, equipment on board aircraft must be tested in situ, or in place, to confirm everything functions properly as a system. Individually, each piece may...

. The book also reveals possible Mars colony

Colonization of Mars

The colonization of Mars by humans is the focus of speculation and serious study because the surface conditions and availability of water on Mars make it arguably the most hospitable planet in the solar system other than Earth...

 designs and weighs the prospects for a colony's material self-sufficiency and for the terraforming

Terraforming

Terraforming of a planet, moon, or other body is the hypothetical process of deliberately modifying its atmosphere, temperature, surface topography or ecology to be similar to those of Earth, in order to make it habitable by terrestrial organisms.The term is sometimes used more generally as a...

 of Mars.
The Mars Direct plan was originally detailed by Zubrin and David Baker in 1990.