The Library of Congress does not list any author called Keith Andersen; since that appears to be a typo, that author page is combined here.
#1 Keith Anderson 1929-, A to Z of Classical Music.
#2 Keith Anderson 1946-, On Your Own Again: The Down-to-Earth Guide to Getting Through a Divorce.
#3 Keith (Keith R.) Anderson 1949-, Is This the One?: 9 Tests for Marriage.
#4 Keith Anderson, How to Build Practical Firearms Suppressors.