Donald Kagan, The Peloponnesian War
Bruce Ackerman, The Failure of the Founding Fathers: Jefferson, Marshall, and the Rise of Presidential Democracy_________________________________________
I've been meaning to buy and read Kagan's work for some time now. It is - as far as I know - a distillation of his four volume series on the era in question for a more popular readership. I've read sections of that original series, but never the whole thing.