+1 to Beer in America, it's a great read. I can also vouch for the classic style series installments of Scotch Ale (Greg Noonan) and Pale Ale (Not sure who the author is, some English fellow)Here are two that I bought on Amazon recently:
"The Theory and Practice of Brewing" written by Michael Combrune in 1804. It is the first scientific brewing text.
"Beer in America the Early Years -- 1587 to 1840" by Gregg Smith
I 2nd this, both great books!I found a lot of great historical information in Radical Brewing. It's the first book that I recommend to people who are interested in the overall history of brewing because it covers many different aspects and areas. There might be better books but I've read quite a few and it's my favorite in this respect.
To really dig into the history of specific styles I would recommend the Brewer's Publications various Style books. For Belgian Beer history, I would highly recommend Brew Like a Monk.