One might come to Thérèse Finds Happiness as one might approach a Marquis de Sade novel; and one may be pleasantly surprised, or disappointed, depending on which way you lean. In either case this is a great novel: it's lots of fun and the book "works" on multiple levels: libertinage, comedy, age of Enlightenment philosophy (think Rousseau, Ben Franklin).
The book is divided into four sections really, and there is a case to be made that maybe not all of them were written by the same person or at the same time. In any case, it adheres and quite well. The first section is about Father Dirrag and Mademoiselle Cadiere (anagrams for real-life characters), the second is the Enlightenment section if you will: dialogs between Mme. C*** and Abbot T***, with some sex interspersed to cheer it up. The third section is Bois-Laurier's section, she's a prostitute who is also a virgin -- lot's of opportunity for fun and laughs here. The final section is the denouement. You'll have to read it.
The first section (Father Dirrag, &c.) is in the same genre as a Marquis de Sade novel -- just what one might expect, in it's own way though, -- and one might at first glance think it was inspired by something out of the infamous marquis's novel Justine, but actually it's just the other way around: Justine was published (in 1791) over 40 years AFTER Thérèse Philosophe came out (in 1748). de Sade clearly read Therese and has said so himself.
In terms of where this novel falls in categories or genres, Thérèse Philosophe was published about 8 years after Richardson's Pamela, which latter novel was originally cast as conduct literature, but clearly crossed the line toward libertine literature (let's call it soft-libertinage); the British censures of Pamela thought so as well (libertinage; maybe not so good a vehicle for young people's conduct).
Thérèse Finds Happiness, this modern translation, is libertine literature, but of a soft-core variety (your mileage may vary however).
What might surprise most readers is that Thérèse Finds Happiness is *very funny* -- in many places. If you like Gargantua and Pantagruel by Rabelais, you'll probably love the section on Bois-Laurier.
Thérèse Finds Happiness is Thérèse Philosophe or Thérèse The Philosopher -- the name was changed for this publication and translation to make it modern and also to emphasize that this novel is above all a comedy: nobody dies in it (nobody of importance anyways), and the heroine of the story ends up happy. It's a lot of fun.
If you can read French, even if haltingly, you should read the novel in the original. But if you can't, or don't want to be bothered looking up words in a dictionary, or puzzling over the somewhat strange spelling of words from 18th century France -- this is the new English translation for you. It's translated to keep the verve and flavor of the original, but in a modern way. (For instance, things like "Thank you so much," which people didn't really say ten years ago even. They said simply "Thank you").
Lots of fun and sex, if you like that sort of thing. A little (just a little) flagellation. And a faithful translation to boot (I know, because I translated it). But don't take my word for it...