Love is the most important resource of every human being’s life. The authors examine what kind of roles love might have in different phases of life. They discuss how love makes life more meaningful and enjoyable. However, there are still love-related themes that are not so easy to discuss or accept. This book provides research-based analyses about the different roles of love including forms that have aroused contradictory feelings and prejudices, such as falling in love in the old age and love in people with intellectual disability are discussed. The book serves as a textbook for studies in psychology, education, and other fields in human sciences.