"The Colt Revolver--1836 to 1940" by Haven and Belden is a famous reference. It can often be found at gun book sellers online. It's been reprinted many times.
James Servin's(sp?) book on Colt revolvers is the best Colt reference available.
Try thess book sellers, they have the best old Colt references:
The spelling of the author's name for the second book Dfariswheel lists is James Serven. The book is Colt Firearms, Serven Books, Santa Ana, California, 1954.
BTW, if your interest is in pre WWII Colt target revolvers,
there is a Yahoo Group. You can probably get some help here for any pre war Colt, or you can try the Colt Forum, a bbs that is unfornately less than busy.