Clarence began his writing career in 1977 as editor for Pulitzer Prize-winning reporter, Robert V. Cox, rewriting his unpublished manuscript, Deadly Pursuit; the book soon became a commercial success, followed by a Monday Night television movie special. He wrote his first novel, Cloudland, in 2002 and his second novel, The Borshov Effect, in 2003. The following year, he moved to New Mexico for a major writing assignment. The move to Las Cruces was in many ways a first for him personally and as a writer as well.