This volume contains the proceedings of an international conference on the relation between asceticism and aspirations about reaching for perfection held at the University of Leuven 21-23 October 2019 and organised in the framework of Kosmoi, an association of Leuven colleagues from various disciplines working in the field of religious studies. Contributors were asked to integrate in their essay (aspects of) one of the following four basic topics: (1) the goal and purpose of living an ascetic life; (2) the means, both material and immaterial, available for reaching this goal; (3) the place of asceticism within the whole of religious practices in a particular religious tradition; and (4) the challenges and dangers of adopting such a lifestyle. These topics are addressed in various religious traditions, with a focus on Christian tradition - Western and Eastern, and through various approaches - historical, anthropological, and more philosophical.