All the ones cited by soot, especially Gilbert's and Crowley's, but I highly recommend David Stevenson's Cataclysm: The First World War as Political Tragedy. It came in 2004, and he had access to materials Gilbert didn't. He is also somewhat of a revisionist, a legit one in the real meaning of the word,

It is an excellent book, with a pretty detailed accounting of French materiel production, a truly amazing feat of production and deployment that isn't normally covered by earlier books, a feat easily comparable to the much admired Russian production feats in WW II, as well as a lot of other factors that one rarely considers and most histories gloss over, preferring to cover specific battles or some such.

But, it also goes behind the scenes of politics and command decisions, errors, etc., as well. It is fairly comprehensive, loads of stats and timetables. Of course all of this makes for fairly dense reading, and it won't be a quick read, but certainly good reference material.

I would also add Barbara Tuchman's Guns Of August for aquick read, though not nearly as detailed as Stevenson's account.

I'm sure there many excellent European academic books on WW I that haven't been published in English editions; in fact many better ones, but Stevenson's is the best one available to me, in any case.

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