Jay Robert Nash has written more than seventy books, mostly encyclopedia-style books and reference works about crime. Nash currently lives in Wilmette, Illinois and describes himself as an "entrepreneurial businessman." He is the recipient of a Special Edgar Allan Poe Award, in 1991, for his six-volume Encyclopedia of World Crime.

Nash has won "Best Reference" citations from the American Library Association for four of his books, including Darkest Hours. However, he has repeatedly said that his books are "seeded with information to detect any unauthorized use or duplication"; the precise nature of these copyright traps may include incorrect information in otherwise factual entries, or wholly fictitious entries. Sally G. Waters, writing for the Library Journal, called Nash's work "fascinating yet flawed" and recommended that it be used only for background research, verifying the information based on the sources in Nash's bibliography.In the Journal of American History, Richard Maxwell Brown also noted the "numerous errors, omissions, inconsistencies, and anomalies" in Nash's encyclopedias. In 2008, The Library of America selected Nash’s story “The Turner-Stompanato Affair” for inclusion in its two-century retrospective of American True Crime.

Nash once filed a lawsuit against CBS for producing an episode of Simon & Simon with a plotline based around his notion that bank robber John Dillinger was not killed by the FBI in 1934. (Nash focused two separate books on his theory, which has won little acceptance from historians.) His claim of copyright infringement was dismissed on summary judgment, a ruling upheld by an appeals court. The court compared Nash's writing to "speculative works representing themselves as fact" and concluded that he could not claim a copyright on his analysis of historical facts, only his expression of them. The court added that Nash should not be surprised at the result, pointing out, "His own books are largely fresh expositions of facts looked up in other people's books."

Nash has published more than 70 books over the years. Among these are:

• Ballistics
• Bloodletters and Bad Men Lucky Luciano to Charles Mason; A Who's Who of Vile Men (and Women) Wanted For Every Crime in the Book published by M. Evans and Company, Inc., revised and updated edition (1995).
• Citizen Hoover
• Concise Encyclopedia of the Civil War
• Crime Movie Quiz Book
• Crime Scene Investigations
• Cyber Crime
• The Dark Fountain published by Signet (1988).
• Darkest Hours: A Narrative Encyclopedia of Worldwide Disasters from Ancient Times to the Present published by Pocket Books (1977).
• Dictionary of Crime: Criminal Injustice, Criminology, & Law Enforcement published by Marlowe & Company (1994).
• The Dillinger Dossier
• Encyclopedia Of Civil War Battles published by Scarecrow Press (2005).
• Encyclopedia of Western Lawmen & Outlaws
• Fingerprint Identification And Classification
• Forensic Anthropology
• Forensic DNA Analysis
• Forensic Psychology
• Forensic Serology
• Forensic Toxicology
• Forensic Pathology
• The Great Pictorial History of World Crime published by Scarecrow Press (2004)
• Hustlers and Con Men: An Anecdotal History of the Confidence Man and His Games published by M. Evans & Company (1976)
• Look for the Woman: A Narrative Encyclopedia of Female Poisoners, Kidnappers, Thieves, Extortionists, Terrorists, Swindlers and Spies from Elizabethan Times to the Present published by M. Evans & Company (1986).
• The Mafia Diaries published by Dell Publishing Company (1986)
• The Motion Picture Guide published by Cinebooks during the 1970s and early '80s. This was a twelve volume reference work.
• The Motion Picture Guide published by Cinebooks beginning in 1985, this is an annual book.
• Murder Among the Rich & Famous published by Random House (1988)
• People to See
• Spies: A Narrative Encyclopedia of Dirty Tricks and Double Dealing from Biblical Times to Today published by M. Evans and Company, Inc. (1997)
• Terrorism In The 20th Century: A Narrative Encyclopedia from the Anarchists, Through the Weathermen, to the Unabomber
• World Encyclopedia of 20th Century Murder published by Paragon House Publishers (1992)
• World Encyclopedia of Organized Crime published by Paragon House Publishers (April 1992) ISBN 1557785082