Jean Meslier, perhaps the least restrained freethinker of the French Enlightenment, is also one of the most notorious examples of apostasy. As curé of the village of Etrépigny in Champagne from 1689 to his death, Meslier lived in complete obscurity, attending to his pastoral duties. But under the innocuous exterior of the humble Catholic priest, there seethed a violent hatred and passionate disavowal of the religion that it was his ironic profession to serve. Having resolved sometime in the 1720s to compose his only work, the Testament, with the aim of keeping it secret until his death, he felt free to vent fully the anti-Christian, atheistic, revolutionary—indeed, anarchistic—sentiments that he had been obliged to suppress beneath a lifelong mask of prudent duplicity. The available biographical facts are unfortunately too meager to clarify this extraordinary personality. It is known, however, that on one...