In the 1990s, a South African nurse walked into a hospital with an unusual problem: Her sweat was red. And thus was born “The Joy of Sweat: The Strange Science of Perspiration,” a chatty, informative romp through the science and history of perspiration. The first section of “The Joy of Sweat” explains the basic underlying principle: If your skin becomes wet and moisture evaporates off of it, you will cool down. ADVERTISEMENTNow, long after we lost our fur, sweat and stink are still inextricably bound up in our social fabric. In the middle section of her book, Everts travels around Europe to a variety of kooky events and intriguing labs to research sweat and stink.