Crispin died Friday of bladder cancer at the Hospice of Charles County in Waldorf.
Crispin wrote many original books, but is famous for her tie-in novels that provide the background and emotional development of film characters, The Washington Post reported.
She wrote a series of novels based on "Star Trek," as well as three books based on George Lucas' "Star Wars" movies.
She also helped found the watchdog committee Writer Beware, that alerts people to agents and publishers who seek to scam writers.
Crispin helped uncover hundreds of cases and helped send several scam artists to prison, the Post said.
Crispin received a bachelor's degree in English from the University of Maryland in 1972.
She is survived by her husband of 12 years, Michael Capobianco, who is also a science fiction author, as well as a son from her first marriage.