The question we asked this year of the members of the Society of American Historians, and several other scholars, was simple: What is the one mystery in United States history you would like to see resolved? And what do you imagine is a plausible solution?

To encourage their responses, we added that the missing minutes of the Nixon tapes was an obvious example of what we had in mind. And what Aaron Burr was up to was another. But we were sure there were many other mysteries from all eras of our past—ones that involved people, events, and social and economic patterns. Finally, to forestall any objections that considerations of this kind might be seen as trivial, we quoted the words of that wonderful seventeenth-century philosopher Thomas Browne: “What song the sirens sang, or what name Achilles assumed when he hid himself among women, though puzzling questions, are not beyond all conjecture.…”

The results follow. If nothing else, they prove that history is never fully disclosed; the case is always open.

—The Editors

What Made Burr Tick? Was Jefferson Guilty? What Turned Madison Around? How Did Meriwether Lewis Die? What Was the Truth of Andrew Jackson’s Marriage? What Was Bugging James Monroe? What Did Key See? Who Owned the Slaves? If Virginia, Why Not Maryland? Did Stanton Betray Lincoln? What did Lincoln Really Think? Were Sacco and Vanzetti Guilty? Was Hiss? Who Invented the Hamburger? Who Shot Huey Long? Who Are the Childs Brothers? Did FDR Think He Was Immortal? Why Was Wadheim Cleared? What’s Wrong with This Picture? What Did the Kremlin Want? Did the White House Trigger the Challenger Catastrophe?