How long was the male co-writer of "Pools of Darkness" employed by TSR, Inc? 
Pools of Darkness (novel): Pools of Darkness is a novel based on the "Pools of Darkness" computer role-playing game. Pools of Darkness (novel):  It was written by James Ward and Anne K. Brown, and published by TSR in February 1992. Jim Ward (game designer): James M. Ward (born May 23, 1951), is an American game designer and fantasy author. Jim Ward (game designer):  He is most well known for his game development and writing work for TSR, Inc., where he worked for more than 20 years.
more than 20 years