This is a book of trust. To all the people who taught me with the stories of their lives—the people who fill these pages and the many more who fill my thinking—thank you for your trust and your teaching. And thank you to the scientists and therapists who gave their time so generously to educate me.

Among my sources of learning is the photography of Ron Parisi, whose story I tell in “The Devotee.” His work can be found at www. ronparisi. com

This is also a book that required a great deal of faith. For that and for all her guidance, I have long been very lucky to have Suzanne Gluck as my agent—and I am lucky to have William Morris’s Sarah Ceglarski, Raffaella De Angelis, Tracy Fisher, Erin Malone, and Cathryn Summerhayes on my side.

Then there is Lee Boudreaux. When we first met, I thought, I want her for my editor. My instincts were only half right, in that I guessed only half of what a wonderful editor she would be. And Dan Halpern, along with Rachel Bressler, Alison Former, Abby Holstein, Van Luu, Michael McKenzie, Greg Mortimer, Allison Saltzman, and the sales team (whose readings, starting with Jeanette Zwarf s, were so thoughtful) have made Ecco a perfect home.

Ilena Silverman, my editor at the New York Times Magazine, gave this book its beginning and offered crucial friendship throughout its writing.

For friendship, faith, guidance, my endless gratitude to Samantha Gillison, John Gulla, William Hogeland, Roland Kelts, George Packer, Ayesha Pande, and Elissa Wald.

And then:

KSF, you are in every word.

Nancy, without you, there would be no words.

And Natalie and Miles, who changed my life, without you there wouldn’t be much of anything at all.