Grays Sports Almanac

"You see this book? This book tells the future. It tells the outcome of every major sports event till the end of the century...football, baseball, basketball, horse races, boxing... the records in this book is worth millions, and I'm giving it to you."

- Old Biff Tannen to his younger self about Gray's Sports Almanac. "I told you, it's all in this book. All you got to do is bet on the winner and you'll never lose."

- Old Biff telling his younger self about the Grays Sports Almanac before giving it to him.

The Grays Sports Almanac: Complete Sports Statistics 1950-2000, also known as Grays Sports Almanac, is a sports book that contain every sporting event in between years 1950 and 2000, that plays a big role in the sci-fi/comedy movie sequel Back to the Future Part II. The Almanac was used by old Biff, so he could alter the timeline, so his younger self can become rich and all-powerful.

History
On October 21st, 2015, after Marty McFly prevented his future son from going to prison, he decided to buy a Sports Almanac. He was originally planning to use the Almanac to cheat at gambling to, "place a couple of bets", and make some money. However, Doc Brown eventually found out, and was upset with Marty's decision, that Marty was going to use the Sports Almanac and the time machine for financial gains, and decided to throw the Almanac in the trash. But while that was going on, old Biff Tannen overheard their conversation about the Almanac and the time machine. So Biff decided to use the Doc Brown's time machine and the Almanac to his advantage.

After old Biff managed to steal the time machine, he traveled to November 12th, 1955 to give his younger self the Almanac. Old Biff told his younger self that all he had to do was bet on the winner, and he'll never lose. Originally, old Biff thought that it would result in positive outcomes, however, the results for Biff did not last that long. When old Biff returned to 2015, he came out of the DeLorrean in pain while leaving behind the broken tope of his cane inside. Apparently, in the bad alternate future, Lorraine shot Biff sometime in the 1990s, which resulted in old Biff literally being erased from existence in 2015.

The results of Biff getting the Almanac caused a series of events that led Biff into become one of the most powerful man in Hill Valley. In 1958, when he became 21, Biff Tannen instantly became a millionaire overnight by betting on a horse race. As the years went by, Biff kept on betting on various sports events, including football, baseball, basketball, and various other sports, and every time, Biff won every bet, which eventually earned him the nickname "The Luckiest Man on Earth" (as shown on the local Hill Valley Telegraph newspaper). And because of the Almanac, Biff used his money to legalized gambling, purchase the police in Hill Valley, start a company known as BiffCo, dismantled Hill Valley's Clock Tower and replaced it with Biff Tannen's Pleasure Paradise Casino and Hotel, murdered George McFly on March 15th, 1973 (, and no one was able to find out who murdered him), and married Lorraine Baines McFly roughly a few months later.

After finding out, and realizing that it was all his fault, Marty asked Biff about the Sports Almanac. Biff told him that it happened on November 12th, 1955. Biff said that a "crazy old codger with a cane" showed up and gave him the Almanac. He also told Marty that the old man warned him a bout a kid and a wild-eyed old man who claims to be a scientist, would come and asked them about the book, and if that ever happens, Biff should kill them. Marty managed to escape and both he, and the Doc traveled to 1955 to destroy the book. After a series of events, Marty was able to grab the book from young Biff. After acquiring the Almanac, Marty burned it so no one can use it. After Marty burned the book, everything went back to normal, George McFly is still alive, and Biff is still a car waxer.

Trivia

 * Screenwriter Bob Gale has commented that "a book of 50 years of sports statistics, with that many sports in it, would be fifty times thicker... but that's 'movie logic' versus 'real logic'." It was essential to the plot that the book be thin enough to be carried in Biff's pocket, and that it have a dust jacket.
 * The almanac contains an incredible amount of detail, including college football games played on November 12, 1955, and the results of horse races on Biff's 21st birthday in 1958.
 * In an early draft of the sequel, it was contemplated that the almanac would have 5,000 pages, made out of a very thin (if not dustproof) type of paper available by the year 2000.
 * Given that newspapers from the future change as the timeline is altered (due to the ripple effect), it's conceivable that such an almanac would always be accurate.
 * Back to the Future Part II is one of only a few films in which an almanac is a plot device. In the 1939 film Young Mr. Lincoln, the information from an almanac was a critical element in the final reel. The film was directed by John Ford, a director whose work was admired by Bob Gale.