The Book That Tells Everything is the name of a magic book that appears in the comic book story "The Smurfs And The Book That Tells Everything". It is mostly a book with blank pages that have nothing but the page numbers on it. The user of the book must turn to the title page where the book will speak to its user, waiting for a question to be asked. When a question is asked, the book will tell its user to go to a certain page, and the answer will magically appear on that page. However, the book only gives the answers to questions, never addressing possible consequences of following these answers. Also, the book can only answer a certain number of questions at a time before it requires rest to recharge its energies.
Brainy first discovered the book while he was dusting the interior of a cabinet that contained books Papa Smurf had purposely locked away. After testing the book with a few questions, he showed Hefty Smurf what the book could do, and Hefty then asked the book for something that will make him stronger. Eventually word about the book got around to the other Smurfs, who crowded around Brainy just so they could ask the book a question. When the book's energies were depleted, Brainy took control of the book and took it inside his house where he would watch over it and control who gets to ask the book a question and when. However, the other Smurfs wanted to wrest control of the book out of Brainy's hands and so proceeded to force Brainy to give up the book. To counter their efforts, Brainy asked the book for a way that he alone would be able to control it, and the book gave him a voice identification spell so that the book would recognize only Brainy Smurf's name and voice, preventing anyone else from using it without Brainy's permission. Even Jokey, who tried to impersonate Brainy, was unsuccessful in gaining access to the book.
To further restrict access to the book, Brainy had moved into The Old Tower outside the village, which was renovated into his personal sanctum sanctorium, with a special curtained room for the book to be placed in. Brainy would appear in the room dressed in a scholar's cap and gown while Dopey would guide the Smurfs seeking answers from the book up the long winding staircase to the room. Brainy would watch over the Smurf asking the book a question and would prevent them from asking certain questions while ejecting those who take too long in asking the book a question.
When Papa Smurf returned from his trip to Homnibus to find that the book was now in use by Brainy Smurf, and that some of his little Smurfs had fallen victim to the consequences of following its answers, he confronted Brainy in the Old Tower in order to have him give up the book. Brainy refused to do so, believing that Papa Smurf was only jealous of the book's knowledge and fearful that he will someday lose his powers. When Papa Smurf had collapsed after leaving the tower, the Smurfs followed the book's instructions to keep the village leader locked up inside his own house. However, he escaped with some help from a few of his little Smurfs and made a temporary home inside a cave while dealing with more Smurfs that fell victim to the book's answers even as they became more dependent on asking the book for its knowledge.
When Papa Smurf found out that rain was causing the dam to overflow, he went to the Old Tower to warn the Smurfs, but Brainy Smurf told them that he would ask the book for a solution for the upcoming flood. However, the book now needed a rest and everybody ends up waiting for it to recharge, much to Papa Smurf's chagrin. When the dam broke and every Smurf ran except for Brainy Smurf, who was swimming while carrying the book, he found Baby Smurf on a little sliver of land in the torrent. Brainy Smurf wasn't sure of how to carry both Baby Smurf and the book to safety, so he asked the book for help and it responded by telling him that the book was too important and that he should give up Baby. Enraged by that prospect, Brainy tossed the book into the river before grabbing Baby Smurf and swimming to the shore.
It was after Brainy and Baby Smurf were rescued that Papa Smurf told Brainy he had kept the book hidden from all the other Smurfs because it was so powerful it could make one lose his head over it. Fortunately, Brainy had made the right decision in realizing what was more important to him and discarded the book in favor of saving Baby Smurf.