Harry Potter and the Chamber of Secrets

1998, British hardcover Bloomsbury edition from 1999, American paperback Scholastic edition from 2000
J. K. Rowling
American edition illustrated by Mary Grandpre
Harry Potter and the Chamber of Secrets
British edition possibly bought for 11.99, American originally $6.99 but purchase price $3.00
British edition in good shape, American with split spine and possible water damage
B

I think this is a shade better than the first book, if not quite at B+ level.  The plotting is better (even if I still don't get, after all this time, quite what Lucius Malfoy hoped to accomplish and if he knew about Horcruxes), and the characterisation of everyone except the Dursleys (who remain cartoonish and are featured less) has improved.  The Weasleys especially shine, all of them-- the parents, Percy, the twins, Ginny, and of course Ron.  Poor Hermione spends much of the time in hospital, so it's not her best book.  (Things will even out more in Azkaban.)  Lockhart is of course a more interesting, and funnier, character than Quirrell, and we even learn more about Hagrid.  The most remarkable thing about this book as compared to the first is that, although still definitely a kids' book, things are getting more complex.  Good guys have flaws, bad guys have redeeming moments, and some people (like Lockhart) don't clearly fall into either category.  Harry, now 12, even doubts himself, when he turns out to be a Parselmouth (snake-whisperer).

As with the first book, there are lots of moments that are "aha!" for those who've read the whole series, but they work fine just in the context of this book, like the Vanishing Cabinet that Peeves breaks as a distraction.  There's less world-building in the sense that not everything's brand-new, and on the surface the story does feel like a replay of the general outline of the first book, down to Gryffindor winning the House Cup.  To make up for that, the familiarity pays off, comedically and otherwise.  The second movie is weaker than the first (especially with the "No Hogwarts without you, Hagrid" ending), but that's definitely not the case with their respective books.  I will say, I liked Grandpre's illustrations less this time around, although the first Lockhart one is just right.