David first began writing "Star Trek" novels at the request of Pocket Books editor Dave Stern, who was a fan of David's "Star Trek" comic book work. His "Star Trek" novels are among those for which he is best known, including "Q-in-Law"; "I, Q"; "Vendetta"; "Q-Squared"; and "Imzadi", one of the best-selling Star Trek novels of all time. He created the ongoing novel series, "," a spin-off from "," with John J. Ordover in 1997. "New Frontier" continued until September 2015, with the publication of the third part of the digital novel, "The Returned", the final "New Frontier" novel to date. David's other science fiction tie-in novels include written five "Babylon 5" novels, three of which were originals, and two of which were adaptations of the TV movies ' and '.