A delightful pseudo-scolarly accound of the Templars, ideal for conspiracy theorists and fans of 'cod-archaeology, and written in a way that hangs together and makes it sound so real.
Presented as drawing on the papers of a recently-deceased (of course, questionably, was his death a suicide, poor driving or....?) academic, this work traces the history of the Order from its inception during the Crusades right up to the present day, mixing fact, fiction and outright speculation skilfully together. It's all there: the Roman Catholic Church, the Freemasons, plot and counterplot, with nods towards prominent works of fiction like Dan Brown's Da Vinci Code - presented as a cunning ploy to discredit the ongoing work of the Inquisition (which covertly runs Opus Dei) against today's Templars.
It all makes for a fascinating read, and like the best fiction, leaves that nagging thought that it just might be true.
For the role-player: Particularly if you like contemporary conspiracy games - Pelgrane Press's Nights Black Agents springs to mind, it would work with Spycraft from Crafty Games too - you will find endless plot ideas here.