A former member of the KGB explains the most valuable technique for espionage

Jack Barsky, former member of the KGB and author of "Deep Undercover," reveals the most important technique for espionage. -------------------------------------------------- Follow BI Video on Twitter: http://bit.ly/1oS68Zs Follow BI on Facebook: http://bit.ly/1W9Lk0n Read more: http://www.businessinsider.com/ -------------------------------------------------- Business Insider is the fastest growing business news site in the US. Our mission: to tell you all you need to know about the big world around you. The BI Video team focuses on technology, strategy and science with an emphasis on unique storytelling and data that appeals to the next generation of leaders – the digital generation.