I own the Esoterrorists, but I was kind of disappointed by it. It's a thin book with a larger than normal font; the "Esoterror" background is somewhat sketchy.
The system itself amounts to three basic concepts:
It's an lightweight system built explicitly around Concept #3, that investigative skills represent how much information you discover, not whether you discover it at all. Still, it didn't seem worth $20 to me.
- Roll 1d6 to match or beat a difficulty factor from 2-8 set by the GM (according to guidelines).
- Skill levels represent points you can expend once per session to modify a relevant die roll.
- Investigative skills don't use a die roll, but expending those points uncovers more information.
Maybe "Fear, Itself" has more meat to it.
"On two occasions I have been asked [by members of Parliament], 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question."
- Charles Babbage (1791 - 1871)