Susan K. Mitchell 
Spy Gizmos and Gadgets [PDF ebook] 

Can you hide a spy camera in a pen or behind a shirt button? Spies need hidden cameras for secret missions. Need to pass along a secret message? A spy might use invisible ink. Spies could not do their jobs without the latest gizmos and gadgets. In this book, readers will check out some of the most important tools in the spy world from wiretaps to lipstick pistols.