In this book Olga Druzhinina analyzes St. Basil's understanding of the church, paying special attention to his Trinitarian approach to its life. Although the role of God the Trinity in the life of the church occupies a considerable place in St. Basil's thought, as Druzhinina demonstrates, it is a subject that has not previously been addressed by scholars. The analysis offered here of the life of the church as grounded in Trinitarian philanthropy provides fresh insights into St. Basil's understanding of the worldwide fellowship of believers. Druzhinina also brings into focus another neglected aspect of St. Basil's ecclesiology--his perception of the church as a two-dimensional, heaven-and-earth mystical reality with a strong bond between both parts (the heavenly and the earthly).