The Lorax is a children's book

Children's literature

Children's literature is for readers and listeners up to about age twelve; it is often defined in four different ways: books written by children, books written for children, books chosen by children, or books chosen for children. It is often illustrated. The term is used in senses which sometimes...

 written by Dr. Seuss

Dr. Seuss

Theodor Seuss Geisel was an American writer, poet, and cartoonist most widely known for his children's books written under the pen names Dr. Seuss, Theo LeSieg and, in one case, Rosetta Stone....

 and first published in 1971. It chronicles the plight of the environment

Environment (biophysical)

The biophysical environment is the combined modeling of the physical environment and the biological life forms within the environment, and includes all variables, parameters as well as conditions and modes inside the Earth's biosphere. The biophysical environment can be divided into two categories:...

 and the Lorax, who speaks for the trees against the greedy Once-ler. As in most Dr. Seuss works, most of the creatures mentioned are original to the book.

The book is commonly recognized as a fable

Fable

A fable is a succinct fictional story, in prose or verse, that features animals, mythical creatures, plants, inanimate objects or forces of nature which are anthropomorphized , and that illustrates a moral lesson , which may at the end be expressed explicitly in a pithy maxim.A fable differs from...

 concerning industrialized society and the danger it poses to nature, using the literary element of personification to give life to industry as the Once-ler (whose face is never shown in any of the story's illustrations or in the television special) and to the environment as the Lorax.
A boy (representing the reader) comes to a desolate corner of town to visit a being called the Once-ler (who is never shown throughout the book except for his arms and hands) and learns about the Lorax.