You've probably seen his enormous (and very good) tome, Postwar, in one bookshop or another. Less likely that you've read his seminal histories on modern French politics. But the most worthwhile of late-historian Tony Judt's work is probably his more recent: the collection of essays, Reappraisals, and just this year (it's at the top of my reading list when I return to the U.S.), Ill fares the land, in which he argues for the continued relevance of the public, the collective, society.
Judt, at NYU, has been struggling for some time with ALS, but continued to provide an impassioned voice in defence of social democracy in our times. That his physical decline and death has been noted by a wider as well as the historian's community is a testament to his contributions to political debate on democracy, Middle Eastern politics and the role of the U.S. in the world.