Seven psalms became known as the Penitential Psalms around the time of Augustine of Hippo. These psalms--Psalms 6, 32, 38, 51, 102, 130 and 143--took on great prominence in the medieval period in culture, literature, doctrine, liturgy, and personal piety. After the Reformation they slowly receded from centuries-long ubiquity, having been all but eclipsed by other texts and concerns. As this rise and fall is explored, well-known figures from the past, including Saint Augustine, Dame Eleanor Hull, Martin Luther, John Donne, Dietrich Bonhoeffer, and C. H. Spurgeon, will be encountered. Less well-known monks, mystics, and martyrs who celebrated these psalms will also lend their voices. Seven contributors chart this narrative across nine chapters. Four other contributors then celebrate the enduring legacy of these psalms in music, worship, preaching, and poetry.