The Nun is a deeply pleasing attack on the institution of nunneries. Diderot was a strong anti-clericalism, but here while he does not attack Christianity at all his target is not so much Catholicism as the actual practice of sentencing young women for life to being nuns in a nunery. The first half of the book is filled with nun-on-nun violence and the second half of the book with nun-on-nun sex. The book could only have been written in the 18th century. Its heroine is a heroine like Tom Jones, Moll Flanders or Fanny Hill who despite whatever happens to them some how comes through with their naiveté and good heartedness intact.
I do not think that it is as good as the other Diderot works that I have read, but it is still a very good work. Amusing and light while advancing the cause of the Enlightenment. Like all of Diderots works it is a humanistic, but subtle and deep work.