The ascetic tracts of 7th century writer Isaac of Nineveh (Isaac the Syrian) provide a wealth of material to better understand early Christian asceticism. By focusing on the role of the body in various ascetic techniques, such as fasting, vigils and prayer, as well as on the way the ascetic relates to the society a picture of asceticism as political activity emerges. For Isaac, the ascetic was to function as something like an icon, an image that showed the world the reality of God's Kingdom already in this life, by clearly indicating the difference between God's ways and men's. Patrik Hagman reviews the scholarly discussion on asceticism of the last three decades, and then proceeds to analyse the texts of Isaac to reveal an emphasis on asceticism as a practice that is at the same time performative, transformative and bodily. This contrasts with the long-established conception of asceticism as based on a negative view of the body. Isaac displays a profound understanding of the way body and soul are related, demonstrating how the body can be used to transform the personality of the ascetic, and to communicate the change to the world, without the use of words. The writings of Isaac offer a rare example of an extensive discussion of asceticism by a person who lived a radical ascetic life himself. Hagman's new study brings Isaac's fresh perspective to bear on an important, yet often overlooked, aspect of the Christian tradition.