I second the motion for choosing Wilson's book first, but I also enjoy having Serven's "Colt Firearms." For Colt semi-autos, Bady's "Colt Automatic Pistols" has lots of info not covered in either of the other two.
Serven's book was my first . I got my first copy as a teen in the 1970's . I studied it so many times that I think i had it memorized for a while .
I just checked my two copies . My first was purchased new in 1979 @ $29.95 cover . The other came in our store with a collection . i had to have it . It is a 1954 copy @ $14.95 . Great book !