Long before Carrie was published Stephen King had written two novels called Getting It On and The Long Walk, both of which he was quite fond of but couldn't quite manage to get published (though Getting It On almost made it to the bookstands). After the runaway successes of Carrie and Salem's Lot, King - obviously in a position of some strength now - decided to resurrect what he thought were good books. On the advice of his publishers however, who cautioned King on the dangers of overpublishing the market, Getting It On - renamed Rage - was published under the pseudonym of Richard Bachman. And a new author was born. Given an identity all his own - which included a cow, a wife, and a son who died in an freak accident - Bachman went on to publish more books and gather quite a cult following, his true identity kept a secret by all those who knew the truth for a long time.

Originally posted by Groucho
Nobody caught on for several years, until King decided to "resurrect" Bachman for "Thinner," somebody did some snooping around, and the cat was out of the bag.