Local librarians are wonderful resources. They know where the information’s hiding, and can save you loads of time. Keep in mind museums often have libraries, too—I searched for days trying to track down the number of Jews from my family’s home town in Poland who were lucky enough to have survived the Holocaust. In a last-ditch effort, I contacted a librarian the US Holocaust Memorial Museum. A gentleman named Jonathan wrote back right away, and voilà—I had my statistic. Librarians can be contacted in person, or by telephone, email and often via live chat (look for a link on your library’s website called “Help/Research” or “Ask a Librarian”).