[moocow]

There area lot of authors who use a pseudonym or two when they are writing a different series or genre of books. Some off hand are Jayne Ann Krentz, Nora Roberts, and I'm pretty sure that Meg Cabot had used different names for some of her series originally.

Stephen King wrote as Richard Bachman. There's another male author I can't recall who wrote murder mysteries, but used a different pseudonym for some books. I guess maybe they want to test the waters, or maybe it's ego, wanting to make it to the top based solely on writing skills.