(written from a Production point of view)
His works include the novels of the "Khan Noonien Singh trilogy" - The Eugenics Wars: The Rise and Fall of Khan Noonien Singh, and To Reign in Hell: The Exile of Khan Noonien Singh; as well as Assignment: Eternity, the Q Continuum trilogy, Devil in the Sky, The Black Shore, and the short story "Night of the Vulture" in the anthology Tales of the Dominion War. Cox's most recent work has been in the Pocket TOS novel series - The Rings of Time in 2012, The Weight of Worlds in 2013, No Time Like the Past in 2014, with Foul Deeds Will Rise following in November 2014.
Cox contributed one of what were intended to be the first novels set in the alternate reality of Star Trek, titled The Hazard of Concealing. The four novels are "on hold" following executive decisions at Pocket. 
An early 2002 interview with Cox was featured in the special features of the Star Trek II: The Wrath of Khan (The Director's Edition) DVD release.