The topic of an optimal or utopian life has received much attention across the humanities and the arts but not in psychology. The German concept of Sehnsucht captures individual and collective thoughts and feelings about one's optimal or utopian life. Sehnsucht (life longings; LLs) is defined as an intense desire for alternative states and realizations of life. Presenting a first effort at capturing this phenomenon, the authors conceptualize LLs as composed of 6 interrelated core characteristics: (a) utopian conceptions of ideal development; (b) sense of incompleteness and imperfection of life; (c) conjoint time focus on the past, present, and future; (d) ambivalent (bittersweet) emotions; (e) reflection and evaluation of one's life; and (f) symbolic richness. Self-report data from 299 adults (19-81 years) support the postulated structure and support predictions regarding the functional role of Sehnsucht. Having LLs was evaluated as providing direction to development and helping to manage life's incompleteness. At the same time, the frequent and intense experience of LLs was associated with lower well-being. When LLs were perceived as controllable, however, this negative association disappeared.