Richard Awlinson
Website http://en.wikipedia.org/wiki/The_Avatar_Series
Richard Awlinson is the pseudonym used for the initial trilogy of the Avatar Series in the Forgotten Realms.
Book One, Shadowdale, was written by Scott Ciencin
Book Two, Tantras, was written by Scott Ciencin and edited by James Lowder
Book Three, Waterdeep, was written by Troy Denning