Better known for his primary role as a Philosoph promoting the Enlightenment (cf. Diderot's work as editor and author of the monumental Encyclopedie), Diderot did what any starving writer would do early in his career: he turned to pornography ("Oh, NO monsieur! It is an erotic novel!) and published it anonymously. Well, word gets around: everyone knew he wrote it, and he served a light jail sentence.
I tried to read this novel the first time many years ago when I was learning to read French, and was happy to see it in translation (except for the occasional 18th century text on chemistry, I did not have the skill or patience to read any other books to completion).
While I would agree with other reviewers that it is not great literature (when compared with Flaubert, Zola, Proust, etc), it IS a good read.
In part this is for the sheer silly fun of a magic ring that causes vaginas to become indiscrete and tell tales of sexual adventure that would shame the efforts of boys in the locker room.
And partly this is for the historical insights a reader finds in The Indiscrete Jewels. As history of science, the novel is a good example of the active male scientist seeking the truth from passive female nature. As political history, the novel is a good example of how edgy intellectuals like Diderot (or like Galileo before him) had to suck up to royalty (in Diderot's case, King Louis XV and his mistress Madame de Pampadour) in order to gain patronage or at least benign disregard.
It's a quick read, and I recommend it for anyone with a curiousity about those darned French were up to in the mid- to late-eighteenth century.
Favorite Diderot quotation: "There are little testicles at the bottom of our most sublime feelings and our purest tenderness."