I became interested in librarians while researching my first book, about obituaries. With the exception of a few showy eccentrics, like the former soldier in Hitler's army who had a sex change and took up professional whistling, the most engaging obit subjects were librarians. An obituary of a librarian could be about anything under the sun, a woman with a phenomenal memory, who recalled the books her aging patrons read as children--and was also, incidentally, the best sailor on her stretch of the Maine coast--or a man obsessed with maps, who helped automate the Library of Congress's map catalog and paved the way for wonders like Google Maps.