His first book, "The Immense Journey", was a collection of writings about the history of humanity, and it proved to be that rare science book that appealed to a mass audience. It has sold over a million copies and has been published in at least 16 languages. Besides being his first book, "The Immense Journey" was also Eiseley's most well known book and established him as a writer with the ability to combine science and humanity in a poetic way. This book was originally published in 1946. Then, it was published again in 1957, a few years after the Piltdown Man hoax discovery.