Book excerpt: Get ready to infiltrate the dangerous, secret world of criminals and cover identities by way of the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF)—where the world's greatest undercover agents are known as RatSnakes. RatSnakes are rarely, if ever, visible to the public they move among and risk their lives to protect. In fact, thanks to their cover personas, they're often assumed to be members of the clandestine criminal world they investigate. Real-life undercover work is a far cry from the sexy, candy-colored world you've seen in Hollywood movies. Only those strong and clever enough get inside and survive. Vincent A. Cefalu would know. He spent 30 years as an ATF undercover operative, in assignments ranging from the Symbionese Liberation Army to Asian organized crime. He has infiltrated notorious outlaw motorcycle gangs as well as splinter groups of the Ku Klux Klan, and in RatSnakes he provides a transparent look at the organization and the operatives with whom he risked his life. Part field guide, part heart-pounding thrill-ride, Cefalu takes readers on a tour of what it's like to confront death on a daily basis. En route, he gives us a look at the on-the-job techniques of kicking in doors, orchestrating "street theater" to ensnare criminals, and making high-stakes gun buys. His irreverent, explicit stories from the inside are a mix of danger and unexpected hilarity that will have readers laughing one minute and then biting their nails when things break bad. Immersive and brutal, RatSnakes offers an in-depth and eye-opening look into the lives of an elite group of men and women who volunteer to do things most couldn't and wouldn't stomach. Civilians with common sense and good judgment run from danger, while RatSnakes sprint toward it—smiling.