Tor Books
From Halopedia, the Halo wiki
Tor Books is a publisher that publishs some of the Halo books. It is part of LLC which publishes popular fiction, and is particularly noted for its science fiction and fantasy titles. Tom Doherty Associates, LLC, was formed by Tom Doherty in 1980, and sold to St. Martin's Press in 1986. Along with St. Martin's Press, Henry Holt, and Farrar Straus Giroux, it is now part of the Holtzbrinck group.
In March 2006, Tor began releasing DRM-free ebooks through Webscriptions, but Holtzbrinck pulled the project within days of it starting, over Tor's objections.