Edmund Morris' classic, with a prologue that is beyond brilliant--really the best preface I've ever read. This book and its sequel in 2001 were huge influences on my "Great Powers."
Until I read these books, I always wondered how you could put TR on Rushmore with Washington, Jefferson and Lincoln. I no longer consider that a stretch for TR--whatsoever.
Anyone who's read my history-of-America in "Great Powers" knows TR is the pivotal figure in so many ways, not the least of which being the profound influence he had on his cousin--FDR.
If you're only going to read one, read the first, simply because the ride up is always more interesting than the time at the top. As soon as I read this book, I thought to myself, why isn't there a big Hollywood movie of such a seminal figure in our history. Scorsese is making a movie of the book, with DiCaprio in the title role. Scorsese makes a lot of sense, because of the NYC connection.
A third book, "Colonel Roosevelt" is allegedly coming out in a matter of weeks!