SEPTEMBER 11 started something: a new conversation about freedom. No doubt philosophers in their conclaves have been at this all along, but suddenly Americans more generally are being invited to refurbish our views about the core of our heritage.

And so we have a spate of new works with titles like “Why We Fight” and “What We’re Fighting For” and “What’s So Great About America” that give freedom pride of place. Together they enlarge our understanding of this concept, not just as a political principle but as the handmaiden of truth.