Just before midnight on July 30, 1942, German U-boat captain Hans-Günther Kuhlmann peered through the periscope of U-166 at a 5,000-ton steamship running north in the Gulf of Mexico toward the safety of the mouth of the Mississippi River. The SS Robert E. Lee, bearing a name from the last war to touch the Gulf’s shores, was on the final leg of a perilous voyage from Port of Spain, Trinidad, and had, along the way, rescued a number of survivors of ships sunk by U-boats.1 Kuhlmann and his boat were on their first trans-Atlantic patrol, hoping to avoid the substantial antisubmarine forces off the American eastern seaboard in favor of the lightly defended but lucrative petroleum-laden targets in the vast Gulf of Mexico. The U-boat had already sunk three smaller vessels, including a 2,300-ton ship off the coast of Cuba, but the current victim was the crew’s largest. It was also their last.