The field has narrowed a bit since the last time I posted on the presidential candidates' reading choices (back in May, when they were asked to name the most recent fiction book they'd read). This week, Katie Couric asked the candidates "If you were elected president, what is the one book other than the Bible you would think is essential to have along?" (In fact I should note that the field has even narrowed since she asked the question: Giuliani and Edwards are included).
The video and text of the candidates' responses are here, but they're worth examining a bit.
John McCain, perhaps in a continued attempt to prove his knowledge of economics, selected Adam Smith's Wealth of Nations. A standard text in the field, but perhaps just slightly dated in some senses.
Barack Obama and Mitt Romney took the political biographies route, choosing Doris Kearns Goodwin's Team of Rivals and David McCullough's John Adams respectively. Obama said of his choice "[Goodwin] talks about Lincoln's capacity to bring opponents of his and people who have run against him in his cabinet. And he was confident enough to be willing to have these dissenting voices and confident enough to listen to the American people and push them outside of their comfort zone. And I think that part of what I want to do as president is push Americans a little bit outside of their comfort zone. It's a remarkable study in leadership." An excellent choice and well-considered rationale.
Romney said that McCullough's book "connected with me in an unusual way - because of [John Adams'] relationship with Abigail - their closeness, and the extensive letter-writing. You saw something about his heart and character: A truly great leader who made a difference for America. And his example is one I'd want to follow." It is a wonderful book, but I'm not sure Romney would want to run on Adams' presidential record, which is (mostly undeservedly) not particularly well regarded.
Giuliani and Clinton both took the smooth path, choosing The Federalist Papers (Clinton prefaced her choice by saying "I would certainly bring my copy of the Constitution because there was apparently not a copy in the Bush White House to the best I can determine,") while Giuliani was careful to note that his copy of The Federalist also contains the text of the Constitution.
Huckabee picked one I'd never heard of: Francis Schaeffer's Whatever Happened to the Human Race?, while Edwards opted for I.F. Stone's The Trial of Socrates (which, bizarrely, appeared directly after Huckabee's choice when I searched for the Schaeffer title in Amazon).