Simply put, this book is brilliant. Nigel Findley has sorted through the more "popular" conspiratorial organizations that really existed (and presumably still exist today). They have been deftly transformed into something gameable. The statistics are of course in GURPS terms, but most of the information is system-independent.
Findley notes in the introduction that this is a different style of book. The fundamental differences in an Illuminated campaign are background and philosophy. Thus, the book is largely a gaming-based discourse on the philosophy of an Illuminated campaign--paranoia, wheels within wheels, power structures, etc. Even the chapter on characters supports this, discussing the types of people who might get swept up in a conspiracy.
The bulk of the book discusses the wholly Illuminated campaign as much as possible, while still leaving the GM to work out the details. Along the way, suggestions are given for Illuminating an existing campaign. An entire chapter is also devoted to the sort of small conspiracies that might crop up in other campaigns, with suggestions given for a number of genres and GURPS worldbooks. There is even a short suggestion (obviously written pre-CCG craze) for basing a campaign on the classic Illuminati card game.
The illustrations are only of mediocre artistic quality, but they do capture the mood of the book perfectly. Pay special attention to the Alexis Gilliland cartoons. They predate the initial 1992 publication of the book by years, but are absolutely perfect for it.
Regardless of the genre system, every GM should have this book. And the players may want it for countermeasures. But this review should in no way be construed as part of a conspiracy to fill Steve Jackson's coffers. Fnord.
Style: 5 (Excellent!)