Buono and Bianchi, the Hillside Stranglers
There are only two major books on the Hillside Stranglers, both of which are very good. Two of a Kind: The Hillside Stranglers by Darcy O'Brien focuses more on the investigation from the standpoint of the Los Angeles law enforcement agencies, particularly detectives, Frank Salerno and Bob Grogan. Also, this book delves deeply into the monstrous mindset of the killers, Angelo Buono and Ken Bianchi. The other book, Hillside Strangler by Ted Schwarz, is much more focused on the personality and mental problems of Kenneth Bianchi.
Two additional books address Ken Bianchi's multiple personality disorder controversy:
J. Reid Meloy, Psychopathic Mind; Origins, Dynamics, and Treatment
Wilson, Colin and Donald Seaman, The Serial Killers: A Study in the Psychology of Violence. London: Virgin Publishing, 1997.
The Los Angeles Times and the Los Angeles Herald Examiner were used extensively as sources for this feature story.