I bought this as a present for my son, but couldn't resist a quick look myself - and then just had to read the whole thing before I gave it back.
It's well written, with a very dry, understated sense of humour at times. It gives a fascinating and often startling insight into the personalities of the twelve presidents, and a vivid picture of politics in the last two thirds of the twentieth century. Some revelations too - I certainly hadn't realised that Lyndon Johnson was interested in improving welfare and really didn't want to go to war in Vietnam, but did so mainly to avoid defeat by more right-wing opponents (a recurring, and pretty depressing, theme in the stories). Also shows how intelligence and good motives won't necessarily make a good president (they did for FDR, but Jimmy Carter, probably the "best" human being of the twelve, was an ineffective president, while Reagan succeeded largely by being charming, laid-back and an excellent delegator). The parallels with the Roman Empire are telling and well-drawn.
I recommend this to anyone who has the slightest interest in world affairs, or indeed to anyone who fancies a book of immensely readable mini-biographies.