"The Handgun", by Geoffrey Boothroyd should be THE basic handgun reference book, from early times through the 1960's. Amazon.com sometimes has copies.
"Sixguns", by Elmer Keith is another classic.
Until someone has read those, he's pretty blank on the essential elements, or at least, these two should probably be the starters.
One can then specialize in S&W, Colt, Luger or similar references. It's certainly best to read a lot of books before relying too much on Internet info and misinfo.
The Jordan book is a good one, aimed mainly at the police revolver market, circa 1965, and provides many gunfighting truths. I have a copy signed by the author, and value it highly.
Lone Star