In the back of his blockbuster novel, All the Light We Cannot See, Anthony Doerr provides an extensive acknowledgment list. It is not uncommon, of course, for authors to publicly thank those who provided support, but in the novel world it is an element seldom carried out to this extent. Anyone reading the book wonders how, for example, the author became so familiar with radio electronics, and with the intimacies of those caught in the last days of the crossfire of World War II. The acknowledgments show how. Moreover they remind those who write of what it takes to produce a blockbuster. On rare occasions, a book like the nonfiction Tuesdays With Morrie, thin and wobbly but emotionally contagious, becomes iconic. But more often it takes much more work on the part of the author than he or she would imagine at the start. This is, of course, daunting news for those who think that top-of-the-head work will yield a best-seller. The good news is that total immersion is one of the rewards of writing. At some point the writer, having done the extensive homework, becomes the master of the subject, as Doerr became the master of his in a book that offers new light on a well-explored period of history.