O.J. Simpson 'If I Did It' Book Sales Skyrocket After Death, Top Criminology Chart

Sales of O.J. Simpson's "If I Did It" book have exploded since the infamous star's death, with the publication skyrocketing to the top of the charts.

76-year-old O.J. died on Wednesday -- a day before the public found out -- when the Simpson family announced the news ... and reignited interest in the grizzly, 1994 double murders of Nicole Brown Simpson and Ron Goldman.

According to Amazon.com, the world's largest bookseller, "If I Did It" sits in the number 1, 2, and 4 spots (different versions of the book -- audio, abridged, unabridged) in the entire Criminology section. It's also number 8 in the Murder/True Crime section.

"If I Did It" was originally written by O.J. and ghostwriter Pablo Fenjves ... with the hypothetical premise of how Simpson could have killed Nicole and Ron if he had been the perpetrator.

Once news of the book deal became public, there was outrage ... with many believing Simpson was further victimizing the families, and profiting off a horrific crime.

Blowback was so intense, publisher ReganBooks scrapped the project, ultimately paving the way for the Goldman family to acquire the book rights.

They changed the name to "If I Did It: Confession Of The Killer" (O.J.'s working title was never released), and released the book in September 2007.

For decades, a portion of book sales have gone to Fred and Kim Goldman, however, much of the $33 million civil judgment has not been fulfilled.