Irenaeus' soteriology is often celebrated as containing many profound themes-- Christus Victor, recapitulation, deification, and more. Little, however, has been said about how Irenaeus thought these benefit individual human beings, or relate to the Christian's faith, love, or piety. Rather, twentieth-century scholars malign Irenaeus' 'moralism', while modern historians often neglect the question of why theology was a basis for defining and limiting Christian communities. This book elucidates these questions by providing an account of Irenaeus' individual soteriology. It begins with Irenaeus' frequent claim that he wrote Against Heresies for the piety and salvation of his readers. Does Irenaeus, it asks, have a coherent way of relating belief in theological doctrines --even philosophical doctrines-- to salvation? To answer this question, the study first establishes the philosophical foundations of Irenaeus' soteriology: his theology, psychology, and philosophically-informed epistemology. It contends that Irenaeus understands 'faith' as part of the epistemic process-a judgment of the soul. This judgment produces love, an affective state of the soul, which in turn manifests in bodily obedience to God. Faith and love mutually reinforce one another, leading to the preservation of holiness and the growth of righteousness in the believer's soul and body as the Christian walks the 'Way of Life'. Faith and love, holiness and righteousness, logically connect to salvation because they are the sine qua non of the Spirit's salvific presence. Having sketched this vision of individual salvation, the book shows how for Irenaeus piety underlies this entire process and integrates it into the lives of second-century believers. It concludes by further integrating this soteriology with Irenaeus' Greco-Roman context, his reading of Scripture, the embodied lives of believers, and broader themes in his soteriology.