This chapter covers past and present research on romantic love, with an emphasis on recent scholarship in this area. We begin with an overview of definitions and theories of romantic love, continue with a focus on the biological basis of love (including several recent fMRI studies), and finish with an emphasis on maintaining long-term romantic love. We consider research on romantic love from a variety of theoretical perspectives including cross-cultural models, attachment theoretical approaches, evolutionary models, and in light of the self-expansion model. In addition, we consider the dark side of love, which can result in a variety of emotional responses and can potentially lead to loss of self. We also suggest fruitful areas for future research, including the effects of falling in love on the self, the processes and motivations associated with unrequited love, and the course of passionate love over time including potential moderators of that course. All work in this area converges on the idea that romantic love is an essential human experience that is worthy of future study. Though much progress has been made, there is still much to be done.