Barry Mark Eisler is an American novelist born in 1963 in New Jersey, United States. He is renowned for his gripping thriller series featuring anti-hero John Rain, a half-Japanese, half-American former soldier turned freelance assassin. Eisler has also penned a series featuring Ben Treven, a black ops soldier, and his most recent work centers on Seattle detective Livia Lone.

In addition to his novels, Eisler has a strong presence in the political and blogging sphere, contributing to blogs such as CHUD, Firedoglake, The Huffington Post, MichaelMoore.com, The Smirking Chimp, and Truthout. He maintains his own blog titled Heart of the Matter where he discusses politics and language.

Before embarking on his writing career, Eisler spent three years in a covert position with the CIA's Directorate of Operations. He later transitioned into a career as a technology lawyer and startup executive, working in both Silicon Valley and Japan. During this time, he also earned his black belt at the Kodokan International Judo Center. Eisler's bestselling thrillers have garnered prestigious accolades including the Barry Award and the Gumshoe Award for Best Thriller of the Year. His works have been featured in numerous "Best Of" lists and translated into nearly twenty languages. Eisler currently resides in the San Francisco Bay Area, continuing to write novels and blog about crucial issues like torture, civil liberties, and the rule of law.