The Praktikos contains 100 chapters discussing foundational discipline of the ascetic life, namely fighting the passions and their attendant demons. It is prefaced by a letter to Anatolius (otherwise unknown). The work, considered one of his most important, is the first of a trilogy that continues with the Gnostikos and the Kephalaia gnostika. Unusually, numerous manuscripts both attest to the original Greek and attribute the work to Evagrius, rather than reassigning it to Nilus or another less controversial author. The Praktikos exercised an enormous influence on Christian monastic asceticism in the medieval period.