Hammer Carl. Techniques of Secret Warfare: The Complete Manual of Undercover Operations

Miami: Flores Publications, 1996. — 174 p. — ISBN 0-918751-40-3.The most complete, up-to-date information on spying available anywhere! Now you can study the techniques used by real professional spies and investigators. Learn how to gather any type of information you may want-or stop others from getting info on you!
Just take a look at the Table of Contents to get an idea of the many topics covered in this comprehensive book:
The significance of Human Intelligence
Infiltration and Maintain cover
Temporary missions: Methods for gaining entrance to enemy installations; how to open and reseal letters; surveillance techniques
Protracted missions: recruitment techniques
Security: travels; safe houses; hide-outs; clandestine meetings & counter-surveillance techniques; bug detectors
Escapes: Trains and vehicles; ways of evading dogs; escaping from handcuffs
Reporting systems & communications techniques: Letter drops; couriers; civilian postal and telegraph systems; telephone; radio; visual signals; audible signals; simple codes; scrambling systems; invisible ink
Photography: Hand cameras; video cameras; night vision devices
Enemy interrogation techniques & how to counter them.
Examples from real operations and case histories are included to illustrate the techniques described. This is vital information for everyone interested in intelligence-gathering or privacy.