Despite the colossal importance of Augustine in the history of justification, no comprehensive study on this topic has yet been written. Moreover, the prevailing view is that Augustine understood justification to be caused by charity, not faith. This book aims to re-center Augustine’s theology of justification onto faith, and its thesis is that Augustine developed multiple accounts of how faith justifies based on whether faith is motivated by fear (which fails to justify), hope (which will justify), or love (which already justifies). The introduction then establishes the fundamentals of justification for Augustine: Augustine understands justification to consist in forgiveness and interior renewal, interprets iustificare (to justify) as making righteous by grace alone, and understands human iustitia (righteousness) as a created gift distinct from God’s righteousness. Lastly, the introduction shows how justification was central to Augustine, both to counter Pelagianism and to explain the work of God operative in the actions of the Church.