Vanity Fair is an acknowledged classic of English literature. It was first published serially, as was customary, beginning in 1847, and it established Thackeray as a major novelist. It tells the story (in case you don't already know) of two young women, Amelia Sedley, quiet, retiring, loving, and self-effacing, and Rebecca Sharp, clever, pretty, ambitious, and entirely self-centered. The two leave school together but go in different directions. Amelia comes from a rich family; she returns home and expects soon to marry her fiance, George. Rebecca is poor, and takes a position as a governess. Both women encounter changes of fortune, for better and for worse, and although they mostly go their own ways their paths do intersect from time to time.
Vanity Fair is a very entertaining book. In the original serial publication it bore the subtitle, "Pen and Pencil Sketches of English Society," which reflects Thackeray's intention to offer satirical descriptions of various aspects of English life. This he does, frequently interrupting the narrative to comment on the behavior of his characters or the behavior of people generally. For the most part, his comments are amusing, sometimes laugh-out-loud funny, but they do slow down the narrative and there were a few places (not many) where I found them a bit too long and a bit in the way. That, however, is my only complaint about the book, and it is not a serious one. Sometimes in the midst of a digression there is a phrase or a joke that comes as a surprise and makes everything ok again, as when an unattractive woman bestows a kiss that is "like the contact of an oyster."
If you have never read Vanity Fair I encourage you to pick it up. It is a long book, best read when you're not in a hurry--vacation reading, perhaps--but well worth while. If, on the other hand, like me, you read it years ago and have forgotten all but the main outline of the plot, you will find that most of it seems new and amusing and the parts you do remember improve on renewed acquaintance.