Sheril Kirshenbaum (2011). The Science of Kissing: What Our Lips Are Telling Us.‎

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. 

Review by Jessica Gelt, LA Times: http://articles.latimes.com/2011/feb/14/entertainment/la-et-book-20110214

Barry R. Komisaruk, Carlos Beyer-Flores and Beverly Whipple (2006). The Science of Orgasm.‎

Behind its tongue-in-cheek "plain brown wrapper" cover, this unique book offers a thorough compilation of what modern science, from biomechanics to neurochemistry, knows about the secrets of orgasm. 

Interview with Wired News: http://www.wired.com/medtech/health/news/2007/01/72325

Christopher Ryan and Cacilda Jetha (2011). Sex at Dawn: How We Mate, Why We Stray, and What It Means for Modern Relationships.‎

In this controversial, thought-provoking, and brilliant book, renegade thinkers Christopher Ryan and Cacilda JethÁ debunk almost everything we “know” about sex, weaving together convergent, frequently overlooked evidence from anthropology, archaeology, primatology, anatomy, and psychosexuality to show how far from human nature monogamy really is.

Review by Ellen McCarthy, Washington Post: http://www.washingtonpost.com/wp-dyn/content/article/2010/05/27/AR2010052706046.html