Charles Darwin first published On the Origin of Species in 1859, and continued revising it for several years. As a result, his final work reads as a composite, containing more than a decade’s worth of shifting approaches to his theory of evolution. In fact, it wasn’t until his fifth edition that he introduced the concept of “survival of the fittest,” a phrase that actually came from philosopher Herbert Spencer. By color-coding each word of his final text by the edition in which it first appeared, the book traces Darwin's thoughts and revisions, demonstrating how scientific theories undergo adaptation before their widespread acceptance.

The hardcover book is printed in full color, and the type is set in 9.75 point Century Schoolbook.