This course is about the scientific study of love, sex and relationships with an emphasis on the impact of psychological factors in shaping love, sexuality and relationships in humans in different cultures. The content is divided into three parts: the evolutionary perspective on sex and mating, psychological theories of love and intimate relationships, and cultural diversities, with special attention given to the pivotal question of why people fall in love. Students will be required to engage in active learning activities every week to work out tentative solutions to challenging issues related to love, sex, or relationships in the contemporary world, individually as well as in small groups. As this field of knowledge is far from being adequately developed, for many questions there are not yet any definite answers. Therefore, it provides a particularly good setting for students to develop and exercise their critical and creative thinking.