“This is a well-written work that should prove a most valuable source for those interested in intelligence matters.”
“. . . .this book can help us better understand the dark underside of the CIA’s operations during the war of aggression in Vietnam.”
"An intriguing, unusual survey which moves beyond 'memoir' status to examine the foundations of CIA quality and strengths."
"....fascinating and troubling....Sullivan opens bare the controversy, including within the agency itself, over the validity of the polygraph. Gatekeeper sheds considerable light on aspects of what was—and remains—one of the most secretive and controversial U.S. government organizations."
“The polygraph is a much-maligned procedure, but I shudder to think what security and counterintelligence at the CIA would have been without it. John Sullivan was a virtuoso of the ‘box,’ the best examiner we ever produced. He has an amazing inside story to tell, as only he could tell it. His book is a major contribution to the intelligence literature. I found it absolutely riveting.”
“I learned more about the workings of the CIA’s polygraph program from reading Gatekeeper than I learned during the twenty-seven years I served in the Agency’s Directorate of Operations. The polygraph is the CIA’s most important tool for validating the intelligence information it collects and for protecting itself from hostile penetration and peddlers of false information. This book provides a wealth of detail about the growth and maturation of the Agency’s polygraph program.”
“Only John Sullivan would have written Gatekeeper. He had the experience of the perfect insider, and his conscience did not make him a coward unwilling to tell the bad as well as the good. Having often worked closely with John, I agree with his premise that evaluating polygraph results is much more of an art than a science. Among the examiners I have known, John Sullivan was a Rembrandt.”
“CIA’s most experienced polygrapher lifts the shroud surrounding an instrument which plays a pivotal and often greatly misunderstood role in the agency’s personal vetting and agent validation systems. Sullivan demystifies many of the misconceptions about this instrument and the role played by its practitioners. Counterintelligence historians will learn much new and useful information as to how the polygraph was employed in the investigations of CIA turncoats Ames, Nicholson, and Scranage.”
“The CIA censors have taken the handcuffs off John Sullivan. The whole story is out, warts and all, including Operation Bad Apples.”