They both suck

Just read the free one first and then if you feel like you need more consider paying for the other one.

i have read the book on this site. it seems pretty informative. is it enough? 
how many of you can actually tel me thaey used countermeasures and passed? id like to get intouch with one of you (by e mail or MSN) to talk about this issue.
i have a polygraph coming up and i MUST pass it.

I'm not going to advise you on CMs one way or another.  And I've only read the free book.

But I failed a recent exam despite being honest and having nothing to hide.  In retrospect, I think it would have been preferable for me personally to have attempted CMs and failed than to just get shafted.

You would be better off to just give it up.  You sound like you're too stupid to pull it off.

Yes and you get FREE advice from Fred Flintstone too!!!
How could you beat it?

Wombat,

I am a co-author of The Lie Behind the Lie Detector. The countermeasure information included therein is not based on my or my co-author, Gino Scalabrini's, personal experience, but rather on the available polygraph literature, including peer-reviewed studies by Professor Charles R. Honts and collaborators and Department of Defense Polygraph Institute documentation.

I have read the 1996 version of Doug Williams' pamphlet, "How to Sting the Polygraph," which you will find cited along with other sources in the bibliography of TLBTLD. I believe that overall, TLBTLD is better researched, better documented, more informative, and better written than "How to Sting the Polygraph."

Key differences include:

1) Williams suggests breathing countermeasures and the anal sphincter contraction only, while TLBTLD also describes mental countermeasures and tongue biting;

2) Williams suggests that exhaling and briefly holding one's breath (blocking) is the least preferable breathing countermeasure; we have found no documentation to substantiate this notion, however. On the contrary, blocking is one of the Department of Defense's twelve scorable breathing reactions, and it may well be the most commonly occurring one. We see no reason not to use it.

3) Williams blurs the distinction between "control" and irrelevant questions; I think TLBTLD does a much better job explaining "control" questions and how to recognize them;

4) I understand that in the most recent version of Williams' manual (which I have not yet read), Williams suggests using breathing countermeasures and the anal pucker combined during the first chart collection, then just the anal pucker the second, then no countermeasures at all in any third chart collection. I don't think that Williams' suggestion of gradually diminishing countermeasures is necessarily well-advised, however, since it leaves open the possibility that one might show stronger reactions to the relevant questions than to the "control" questions. TLBTLD makes no such suggestion.