Building on Book Five’s considerations of the person and redemptive deed of Christ, Book Six of Matthias Joseph Scheeben’s Handbook of Catholic Dogmatics offers his account of the subjective realization of salvation through Christ’s bestowal of grace. This stands as Scheeben’s fullest treatment of the much-contested notion of actual grace and the issues related to the sixteenth-century de auxiliis controversy concerning predestination and how God moves the human will. Progressing in three parts, Book Six commences with an analysis of the concept of actual grace, establishing how God can move the will without compelling it and providing a richly developed context for understanding God’s motive influence. The second part examines three principal heresies concerning grace—namely, Pelagianism, Semi-Pelagianism, and the Reformation doctrines—using these as a basis for evaluating the Catholic dogmas about grace that were articulated against them. Finally, in the third part Scheeben explores the necessity of grace in light of man’s fallen condition and his supernatural end.