Very brief mentions of a number of books.

Terry Pratchett, Night Watch: Perhaps it's that you need to read a critical mass of the Ankh-Morpork novels to really get them, or perhaps I chose the wrong one; I liked it but not as much as Pratchett's YA, despite the time travel and the revolutionaries.

Sara Ryan, Empress of the World: Girls fall in love at gifted summer camp. I liked the first half much better than the second half; it's a much better book when it's making small sharp observations than when it feels the need to move the plot forward. The secondary characters felt kind of perfunctory, especially Isaac and Kevin, who I kept getting mixed up.

Esme Raji Codell, Vive La Paris: Paris's older brother is getting beaten up by one of Paris's classmates, and won't defend himself. He doesn't believe in violence. Meanwhile, Paris is taking piano lessons from old Mrs. Rosen, who used to live in Paris and who turns out to be a Holocaust survivor.
This is an intense and beautiful look at the meaning of pacifism, of nonviolent resistance, of how we should treat our enemies and those who are cruel to us. In a world that can be dark and cruel, is violence necessary to survive? Is it foolish to think you can avoid violence? This is heavy stuff for a middle-grade novel, and Codell deals with it with amazing sensitivity.

Esme Raji Codell, Sahara Special: Not as good as Vive La Paris because of the I'm So Specialness of the teacher (who feels a bit like an authorial projection), but a good story of a girl who's recovering from the breakup of her family by writing secret letters.

Sherman Alexie, The Absolutely True Diary of a Part-Time Indian: Junior, a nerdy fourteen-year-old on a Spokane reservation, loses it when he realizes he's using the same math textbook that his mother used. He throws the book at his teacher--who forgives him and tells him to get off the rez. When he transfers to the all-white high school 22 miles away, he faces prejudice from both the white students and the people on the rez who call him a traitor. This is an extraordinarily delicately balanced book. There's so much darkness in it and yet Junior's narrative voice has enough distance in it that you don't feel pummeled by the darkness, and a genuine sense of humor shines through the terrible parts.

Sara Zarr, Story of a Girl: When Deanna is thirteen, her father catches her having sex in a car. It's a small town, word gets around, and her life is pretty much ruined. Years later, she is still trying to move on, working in a terrible pizza place, saving up money so that her brother and his girlfriend and baby daughter can move out. There are no easy solutions, but a few small and hard-won gestures of reconciliation.

Stephen Pinker, The Stuff of Thought: Linguist Pinker discusses the relation between words and thoughts, which aren't (in his view) as neat as some would suppose; he takes a hard-line stance against the Sapir-Whorf hypothesis that thoughts are constrained by language. Pinker explores causation (if you cause a window to break by distracting the window installer, that's not the same thing as 'breaking the window'), naming, swearing, and politeness. There's tons of "Wow! I never thought of that before!"
I thought it was great. But I should note that I previously agreed with Pinker on a lot of linguistic issues. He's been criticized for presenting his views as uncontroversial, settled facts when that is in fact not the case, and he's so persuasive you can't imagine that he might be wrong. And this isn't necessarily a good thing when he's basically the only popularizer that linguistics has.