A chapter titled "Catching Some Sleepers" was the only previously-unpublished section of my book, Militant Islam Reaches America (New York: W.W. Norton, 2002, paperback 2003), pp. 145-55, 293-94. It argues for the importance of sleeper cells and then lists 42 tell-tale signs suggesting how to identify sleepers. Until now, I had not posted it on the internet.
The recent publication of Daniel B. Kennedy, Robert J. Homant, and Erick Barnes, "An Insider View of the Sleeper Cell Terrorist: A Face Validity Study," Journal of Applied Security Research, 3(3–4), 2008: 325-50, spurs me to post my chapter. Kennedy, Homant & Barnes test my 42 signs by turning to "a diverse sample of Muslim ‘insiders' to evaluate the 42 characteristics listed by Pipes as being possible indicators of a sleeper" (where an insider is defined as "anyone who grew up in the Islamic religion and culture, and has some knowledge of what it means to be a Muslim in a Westernized society").
I am pleased to report that this analysis "established that the items derived from Pipes constitute an internally consistent scale and that our insider judges adopt a consistent pattern in evaluating the items." (November 2, 2008)