Guide to World Screw Threads, by P. A. Sidders, is written clearly and is also heavily illustrated.
Now in paperback, it is an excellent overview of all standards for users and producers of fasteners, and equipment designers who must specify fasteners.
Guide to World Screw Threads provides encyclopedic coverage of the different types of threads standardized throughout the world. It includes:
Unified and American thread series
American translational and American pipe threads
British threads of Whitworth and non-Whitworth forms
ISO metric threads
French automobile
German and Swiss metric threads.