Interpersonal love refers to love between human beings. It is a much more potent sentiment than a simple liking for another. Unrequited love refers to those feelings of love that are not reciprocated. Interpersonal love is most closely associated with interpersonal relationships. Such love might exist between family members, friends, and couples. There are also a number of psychological disorders related to love, such as erotomania.
Throughout history, philosophy and religion have done the most speculation on the phenomenon of love. In the 20th century, the science of psychology has written a great deal on the subject. In recent years, the sciences of psychology, anthropology, neuroscience, and biology have added to the understanding the concept of love.