***** Gatekeeper: A Memoir of a CIA Polygraph Examiner. By John Sullivan. Published by Potomac Books Inc.,www.potomacbooksinc.com (Web); 292 pages; $27.95.

Gatekeeper by John Sullivan, covers the author’s 31-year career as a polygraph examiner for the CIA. Can you imagine conducting polygraphs on U.S. intelligence operatives at the height of the Cold War, which meant helping to assess who were the good and bad guys during that tense time in our nation’s history?

Then consider that outside of the polygraph division, no one in the CIA liked the polygraph division. Field operatives saw examiners as untrustworthy meddlers. If an agent’s foreign source failed an exam, it represented a significant setback to that agent. There was no love lost, but perhaps some grudging respect.

Sullivan says that the polygraph is only as good as the examiner using it, and he repeatedly notes that its use is “more art than science.” That may leave some readers to wonder about the artistic talent of the examiner who administers their next polygraph.

Sullivan is surprisingly candid about CIA examiners’ lack of basic interview skills in the early days of the program. Sometimes senior officials sought quality assurance, other times they didn’t. Separate from the science of lie detection, Sullivan gives an insider’s account of the CIA through the tenure of several directors. The reader gains insight into the CIA’s mission, as well as some unflattering internal political issues.

The author spills a lot of ink obsessing over whether a polygraph ever caught a CIA spy. Sullivan is anxious to inform us that there was one, but not the notorious Aldrich Ames, during his career. Ames was polygraphed twice, once before his traitorous rampage, and once after. His second polygraph was inconclusive.

Does Sullivan tell the reader how to beat the devilish thing? No, I’m afraid not. Maybe in his next book. But he has had an honorable career protecting our foreign intelligence service.

The book may be of particular interest to anyone involved in criminal justice or personnel security, as well as anyone who works for or with the Department of Defense. It de-mystifys the polygraph while providing some useful background.

Reviewer: Brian Cashman, CPP, is regional director of the Mid-Atlantic states for Comcast Cable Communication, Inc., and a former special agent with the U.S. Naval Criminal Investigative Service. He is a member of ASIS.