Biography
In 1958, his mother, Geneva, was murdered in El Monte where she and Ellroy moved three years after her divorce from his father, Armand. The unsolved killing, and a birthday present from his father a few months later, The Badge by Jack Webb (a book about the Los Angeles Police Department), were pivotal moments in his life as related in his autobiography, My Dark Places.

The autobiography My Dark Places was begun in 1994 after Ellroy's friend, Frank C. Girardot, a reporter for The San Gabriel Valley Tribune, accessed files on the murder from the detectives with Los Angeles Police Department.In the afterword to the 2006 re-issue of his book The Black Dahlia, Ellroy confesses feeling sexually attracted to his mother and that he would attempt to spy on her during intercourse. His inability to come to terms with or understand these feelings led him to transfer them onto another murder victim, Elizabeth Short; throughout his youth, Ellroy used Short as a surrogate for his conflicting emotions and desires. "

In his teens and twenties, Ellroy drank heavily, engaged in some crimes (especially shoplifting and burglary), and was often homeless. After serving some time in jail and suffering a bout of pneumonia, Ellroy stopped drinking and began working as a golf caddy while pursuing his writing. He later said, "Caddying was good tax-free cash and allowed me to get home by 2 p.m. and write books ... I caddied right up to the sale of my fifth book."

He writes longhand on legal pads, rather than on a computer, and prepares elaborate outlines for his books that are several hundred pages long. In connection with The Cold Six Thousand, Ellroy has said that he is through with "genre fiction" and plans to write mainstream novels.

Ellroy is an ardent, outspoken and unquestioning admirer of the Los Angeles Police Department, and he dismisses the department's flaws as aberrations, telling the National Review that the coverage of the Rodney G. King beating and Rampart police scandals were overblown by a biased liberal media. Although he generally appears to be a conservative, some of his habits and opinions are not typically conservative: he opposes the death penalty, favors gun control, and was even a friend and admirer of the works of the late Edward Bunker.

Prior to 1995, Ellroy lived in Los Angeles, California, having divorced his wife, Helen Knode, who authored the 2003 novel The Ticket Out. In 1995, he moved to Mission Hills, Kansas, a suburb of Kansas City. He is currently working on the final (and reportedly largest) volume of his Underworld USA trilogy of novels, which began with American Tabloid and The Cold Six Thousand. Ellroy says it has a title but that title is not the reported one of "Police Gazette." The novel is due for release in late 2007.

In July 2006 Ellroy wrote an autobiographical essay for the Sunday magazine of the Los Angeles Times in which he detailed his relationship with the city he had returned to (again) in early June 2006, and divulged that he is recently divorced (again).

Ellroy was disappointed by the film "Cop" (starring James Woods) as an adaptation of one of his novels. He was then astonished by Curtis Hanson's depiction of his novel L.A. Confidential. On a making-of piece on the L.A. Confidential DVD, he says that Hanson and Brian Helgeland, the film's screenwriters, "brilliantly adapted" his book and that he was "flabbergasted" by what was done with it. Prior to viewing the completed film of The Black Dahlia (based on his book of the same name) he had praised it as a brilliantly depicted film after watching hours of unedited footage of the film. Ultimately, nearly an hour of the three-hour film, which linked events and facts together, was cut from the final version.