Will "Love Will Keep Us Together" or is it true that "Love Is a Battlefield"? Whereas the topic of romance has provided limitless inspiration for artists, writers and musicians, scientists are just as fascinated by affairs of the heart, though they seldom sing about it. Cupid's unpredictable arrow explains little, so it can be more useful to understand how our brains and bodies are biologically involved in choosing the target. In Scientific American's latest eBook, Disarming Cupid: Love, Sex and Science, our editors take a step back and examine romance research that relies on fMRI studies and other tools. Authors in this ebook examine love and sex from a variety of angles, starting with perceived sex differences among men and women, which are discussed in Section 1, "Men Are from Mars, Women Are from Venus," but are we really as different as that? As the opening story shows, few other questions can get at the heart of this debate like "Can heterosexual men and women ever be 'just friends'?" (Spoiler alert: new research sadly suggests that the answer is "no".) Subsequent sections tackle other facets of love, including the implications of the dramatic rise in online dating and how we choose our romantic partners. Section 4, "Sex and Love in the Brain," gets to the meat of the matter, looking at neurology. In particular, the article "All You Need Is Love" finds--or, perhaps for some, verifies--that romantic love stimulates the same brain pathways that an addictive drug would. Section 5 focuses on issues of gender and sexuality. "Do Gays Have a Choice?" analyzes a wealth of scientific evidence and shows that sexual orientation is determined more by genes and environment, than by individual choice. Finally, the eBook grapples with the darker aspects of love, such as the psychology of prostitution and the sex appeal of narcissists. After all, love's paradoxes are part of why it is such an engaging topic for cultural discourse. As Pascal said, "The heart has its reasons of which reason knows nothing." Hopefully, this eBook will change the "nothing" to "at least something." Click here to buy this and other Scientific American eBooks: http://books.scientificamerican.com/sa-ebooks/.