What can science tell us about the most fundamental and unquantifiable human experience—love? Writing accessibly and with enthusiasm, evolutionary anthropologist Anna Manchin considers friendship, family, and romantic love, as well as polyamory, chosen families, queer love, and even the love we feel for pets, celebrities, and deities. Gathering research from biology, chemistry, and sociology, Manchin delves into the causes and lasting value of love, while also examining its darker consequences.