Marital delay, relationship dissolution and churning, and high divorce rates have extended the amount of time individuals in search of romantic relationships spend outside of marital unions. The scope of research on intimate partnering now includes studies of “hooking up,” Internet dating, visiting relationships, cohabitation, marriage following childbirth, and serial partnering, as well as more traditional research on transitions into marriage. Collectively, we know much more about relationship formation and development, but research often remains balkanized among scholars employing different theoretical approaches, methodologies, or disciplinary perspectives. The study of relationship behavior is also segmented into particular life stages, with little attention given to linkages between stages over the life course. Recommendations for future research are offered.