Jonathan Israel, Democratic Enlightenment: Philosophy, Revolution, and Human Rights, 1750-1790. With 1152 pages, a major author, and a clear writing style, this is a major work. I’ve only browsed it.
Zara Steiner, The Triumph of the Dark: European International History, 1933-1939. Repeat the above description but up the number of pp. to 1248.
David Weinberger, Too Big to Know: Rethinking Knowledge Now That the Facts Aren’t the Facts, Experts Are Everywhere, and the Smartest Person in the Room Is the Room. Not out yet; will this be one of the big books of 2012? Probably.