Our father among the saints Nicholas Cabasilas (born 1319/23 in Thessaloniki and died sometime after 1391) was a well known theological writer and mystic of the Orthodox Church. He was born in Thessaloniki and, as a young man, was involved in politics. Little is known of his later life, however, he is remembered for his two treatises, Life in Christ and The Exposition of the Divine Liturgy. These volumes are generally regarded as classics of Eastern sacramental theology.

He was on intimate terms with the emperor John VI Cantacuzenos, whom he accompanied in his retirement to a monastery. In 1355 he succeeded his uncle Nilus Cabasilas, like himself a determined opponent of the union of the Greek and Latin churches, as archbishop of Thessaloniki. In the Hesychast controversy he took the side of the monks of Mount Athos and Saint Gregory Palamas. He is commemorated by the Church on June 20.

The Life in Christ by Nicholas Cabasilas is a remarkable product of Byzantium's last great flowering of theology. At a time when secular humanism was increasingly asserting man's complete autonomy, Cabasilas proclaimed that man's true life lies not in himself, but in Christ. For him, man's redemption in Jesus Christ is not just a matter of history, which can be elucidated simply by scholarly endeavor. It is a saving event in which man is called to participate here and now, in body and spirit as well as intellect, through the sacramental life of the Church. The present translation makes this devotional classic available for the first time in English, while the extensive introduction by Boris Bobrinskoy assesses its place within the history of eastern spirituality.