From the notice at http://www.baen.com/:
Jim Baen was a founding partner of Baen Books, one of the largest independent publishers of popular fiction. Since its inception in 1984, Baen evolved to be one of the leading publishers of science fiction and fantasy, and in recent years a leader in electronic publishing and the fight against encrypted books.
Jim Baen started his career in publishing in the complaints department of Ace Books. He moved on to Galaxy magazine in 1973, where his editorial acumen turned the magazine into one of the leading short story venues of the day. He returned to Ace under publisher Tom Doherty to run the science fiction line. When Doherty left to found Tor Books, Jim went with him and established its science fiction line, purchasing its first 170 titles. In 1984 a deal with Simon and Schuster/Pocket Books gave Jim a chance to found his own independent company. S&S has distributed Baen Books ever since. Recently, Baen Books has enjoyed a string of New York Times bestsellers by such authors as David Weber, John Ringo and Eric Flint. Jim also personally worked with Jerry Pournelle, David Drake, Larry Niven, Charles Sheffield, Lois McMaster Bujold and many other authors who shaped the field of modern science fiction. In recent years Jim continued to develop a whole new generation of science fiction writers.