Zachary Taylor: Soldier, Planter, Statesman of the Old Southwest (Southern Biography). This book is a nice biography which covers the life of President Taylor. The book is available to buy from Amazon and other sites.
Here is a take on the book from an Amazon reviewer:
Of all the presidents I have studied so far, Taylor could very well be the least deserving of the presidency. I think Mr. Bauer is a very good writer and historian, but Taylor is neither a very exciting subject or a very well-documented one (apparently many of his private papers were lost during a sacking of his plantation home during the Civil War).
He was essentially a very average intellect and not very creative either in his politics or his military acumen. Compared to other generals who have risen to the presidency (Washington, Jackson, Eisenhower, Grant), his military capabilities were very dim. His successes in the Mexican War, I think, were due more to capable, think-on-your-feet lieutenants than strategy-making onhis part.
This book confirmed the impression of Taylor that I had formed from reading other works about the era: that he was petty, defensive, couldn't control his temper a lot of the time and was politically naive (not necessarily a bad thing...).
I don't believe a man like him would have been elected today. He benefited from remoteness, little interaction with the press and letting other, more powerful politicians essentially run for him.
Like other presidents between 1845-1860, he also had the misfortune of being president during one of our most challenging periods and when the country was probably really run more by Clay, Calhoun and Webster. You couldn't do much in those days without their support and Taylor seems to have been too naive to either (a) recognize that or (b) go along with it. As a result he accomplished very little during his short tenure. I don't think he would have accomplished much more had he lived longer.
The book itself is well-written but not interesting. Again, I think that has to do more with the subject than the author and I wouldn't mind reading something else by Bauer. Still, if you need to read about Taylor, this is probably your best choice.