Sheril Kirshenbaum, Grand Central, $19.99 (272p) ISBN 978-0-446-55990-4

In the vein of Stephen Pinker’s The Language Instinct, scientist Kirshenbaum examines one of humanity’s fondest pastimes. Divided into three parts, the book covers the evolutionary and cultural history of the kiss, the chemistry of kissing, and the future of kissing. In part one, “The Hunt for Kissing’s Origins,” Kirshenbaum examines the role kissing played in the Middle Ages–a businesslike kiss was employed as a legal way to seal contracts and business agreements. Many men did not know how to read and write, so their signature X was kissed to make it legal. Part two, “Kissing in the Body,” will appeal to anyone who has ever been curious about the chemical properties of butterflies in the stomach. Kirshenbaum writes just as gracefully about prostitutes in pop culture as she does the myriad of complicated biological and chemical processes that science uses to explain osculation. Part three, “Great Expectations,” covers Kirshenbaum’s personal attempt to further investigate the kiss and leaves a long list of fascinating questions that demand further research. (Jan.)