What I'm reading now:
The Mitfords: Letters Between Six Sisters edited by Charlotte Mosley
I'm one-eighth of the way through it (834 pages, it weighs a ton). The letters of those terribly well-bred aristo Mitford girls; two socialsts, Nancy and Jessica; two fascists, Unity and Diana; a gentlelesbian farmer, Pamela; and the Duchess Deborah. I've read all of Nancy's and Decca's books, so the letters, spanning eighty years, from the early part of the last century up to just a few years ago, are a fascinating, heart-breaking, at times funny (how they tease each other!), complicated personal history in themselves.
I'd heard Scott Simon's NPR interview with Charlotte Mosley and Debo last week and just had to run out and buy the book. "Their lives reflected the passions and torments of the 20th Century."
The Guardian has a good review.