Mario Spezi (July 30, 1945 – September 9, 2016) was an Italian journalist and author. He wrote the non-fiction true crime book The Monster of Florence with American author Douglas Preston. Additionally, he was credited by Preston for providing details used in the novel Brimstone.
Spezi spent much of his career tracking the case of the notorious serial killer known as the Monster of Florence. He was even jailed on charges of impeding the investigation by prosecutor Giuliano Mignini, though the charges were overturned on appeal.
Spezi also wrote the film Il Mostro Di Firenze (1986), based on his novel. The film aired in Italy and the United States.
- Il Mostro Di Firenze (1983)
- Ritratti distratti: [catalogo della mostra a] Firenze, Loggia Rucellai, maggio-giugno 1988 (1988)
- Der Engel mit den Eisaugen with Douglas Preston, ed. Knaur, Germany (2008); on Amanda Knox case
- Preston, Spezi 2008, Chapter 6.
- Douglas Preston; Mario Spezi (June 19, 2008), The Monster of Florence, Grand Central Publishing, ISBN 978-0-446-58119-6.