According to the LA Times
Ackerman, a writer, editor and literary agent who has been credited with coining the term "sci-fi" in the 1950s, died Thursday of heart failure at his home in Los Angeles, said John Sasser, a friend who is making a documentary on Ackerman.
Ackerman was 92 when he passed away and an inspiration to many. One of the ways he influenced our generation and those that came before us, was his position as editor of Famous Monsters of Filmland. Though of his more famous achievements he was the writer/creator of the characters Vampirella and Jeanie of Questar.
He was a huge fan of all things fantasy, horror, and sci-fi which as stated in his LA Times Obituary, he was
a man who actually had known Lugosi and Karloff and whose priceless collection of science-fiction, horror and fantasy artifacts ran to some 300,000 items.
Which could possibly be the largest in the world, if not close.
Watch Forrest J Ackerman brief history of early Sci-Fi video here
His death is a great loss to all of fandom across the greater Speculative Fiction genre.