A winner by the grandaddy of badge collectors. I first came across this guy when he was writing for Guns Magazine. He's published several books on police collecting, but this is one of the best.

The Mail Cover, also by somebody else. I got a few of these when I bought International Police Equipment Company back in the 1980s. It was published by IPEC under their previous name, Investigators Information Service, which was a partnership between Herb Green and Joe Karbo of The Lazy Man's Way to Riches fame.

I have a few of those books put out by Jews for the Preservation of Firearms Ownership, The Uncle Jack Series. Probably by Aaron Zellman. Him or L. Neil write most of the stuff he sells.

Mail Order Madness.... I writ that one.