"Killers are made, not born." That quote is taken from Ian Brady’s book The Gates of Janus, and it rings true for many convicted serial killers and murderers. His book and other autobiographies and crime novels by murderers offer a bizarre look into the authors' dark pasts, twisted minds, and horrific crimes.

Letters and books written by serial killers aren’t new. But rules commonly known as Son of Sam laws, which prevent criminals from profiting the publicity of their crimes, weren't implemented until the "Son of Sam" case brought widespread media attention in 1977. Before that, scary serial killers like H. H. Holmes often received payment in exchange for writing about their dark deeds - or even penning a confession.

In these books by killers, some authors, like Jack Unterweger and Carl Panzram, explicitly recall their murders. Others, like John Wayne Gacy, use the text to attempt to prove their innocence. Whatever the specifics, these books written by serial killers hold grisly fascination for fans of true crime and curious historians alike.