The Thing Itself: On the Search for Authenticity by Richard Todd. Riverhead. 272 pages. &16.47 Probing inner truth in this edgy moment, Richard Todd finds much that feels inauthentic, empty, drained of meaning. Once executive editor of The Atlantic Monthly, Todd’s been paying attention a long time and he lives in a place reeking with history, western Massachusetts. He wants to know the source of this malaise and why we hunger after authenticity—and what is that, anyway? In our neighborhoods …