S. Hussain Zaidi is an Indian author and former investigative journalist. He is also known to be India's number 1 crime writer, and most prolific crime writer. Zaidi began his career in journalism while working for the newspaper The Asian Age, where he became the resident editor. He later worked for several other periodicals, including The Indian Express, Mid-Day and Mumbai Mirror. His in-depth research on the Mumbai mafia has been used by international authors, including Misha Glenny in McMafia and Vikram Chandra in his book Sacred Games.

Zaidi has covered the Mumbai mafia for several decades. His 2002 book Black Friday detailed the 1993 Mumbai bombings, an attack consisting of thirteen explosions that killed 250 people. The book was adapted two years later, in 2004, into a film by Anurag Kashyap also titled Black Friday. The film was so controversial that the Indian Censor Board did not allow it to be released in India for three years. It was finally released on 9 February 2007 after the Supreme Court of India allowed it following the TADA court verdict in the '93 Bombay blast case. In Dongri to Dubai: Six Decades of the Mumbai Mafia, a historical account of the Mumbai mafia, Zaidi conducted an interview with crime boss Dawood Ibrahim, who is suspected of having orchestrated the bombings. The book was adapted into the film Shootout at Wadala by Sanjay Gupta.

Zaidi was also an associate producer of the HBO documentary Terror in Mumbai, which is based on the 26/11 attacks in Mumbai. He is also the founder of Blue Salt Films.