Jo Walton is one of my favorite novelists; books like Among Others (which justly swept the field's awards in 2011) and the Farthing/Ha'penny/Half a Crown novels show incredible insight into people, a deft hand at explaining the struggle to do good in bad situations, and the ability to spin out moving, heart-rending conundra that make you ache for all concerned. (Not only that, but she's got a book due in May that is radioactively good, a book that kept me up all night weeping and laughing by turns, and that has sunk a barb in my heart ever since).
But she's also a spectacular literary critic. Her regular column on Tor.com, through which she re-reads her favorite books and explains what makes them work, is required reading for anyone seeking to understand how books do their magic trick. And now those columns have been collected into a single volume, called What Makes This Book So Great.
Through dozens and dozens of essays, Walton introduces a spectacularly broad range of material, including material that is badly flawed, and finds in each book the kernel of artifice and art that makes it work. From Heinlein's Friday (The Worst Book I Love) and Pournelle's Janissaries (which Walton identifies as a cure for bad cramps) to forgotten gems like The Mindwarpers and classics like Dhalgren.
Walton's critical gift is her ability to help you love your favorites even more, and to be fascinating, at length, on books you don't give a damn about. This is a remarkable guided tour through the field -- a kind of nonfiction companion to Among Others. It's very good. It's great.