18th-century art critic, philosopher and writer Denis Diderot finished The Nun around 1780 and it was a successful scandal in secret circulation until after his death when it was finally published in 1796.  It reveals the unnatural life of the convent by mingling "mysticism, madness, sadistic cruelty and nascent sexuality" and is an absolutely compelling read.

The Nun by Denis Diderot and Translated from French by Russell Goulbourne