The suntan experienced a profound change in the last century. Considered a mark of the lower class for hundreds of years, tanning became a fad in the early 1920s and remains popular today. The tan, though, was much more than a matter of fashion, enjoying at first a boost from the medical establishment. Opinions ranging from hard science to quackery lauded the suntan as something of a panacea. Near the end of World War II, however, researchers...