Why was the book in a Strange important?

In the 1967 short story "I Have no Mouth, and I Must Scream", by Harlan Ellison, the book is an important tool in the survival of the last five human beings. The book is a collection of all human knowledge, compiled by the supercomputer AM in order to keep the humans entertained and make sure they do not go insane from their isolation from the outside world. The books allows them to experience all of human history and culture, as well as providing them with a source of inspiration for their survival and continued existence.