The so-called "F tima prayer"--O my Jesus, forgive us our sins, save us from the fires of hell, and lead all souls to heaven, especially those in most need of thy mercy, amen--due primarily to its widespread use as a rosary decade prayer, surely ranks among the Church's most popular prayers. Despite its brevity, it is a prayer of remarkable theological depth--not to mention, daring. In the space of just twenty-nine words, it broaches some of the great themes of Christianity: sin, forgiveness, mercy, heaven, hell. It also touches on two hot topics within contemporary Catholic discussion--having a personal relationship with "my Jesus, ' and the permissibility of hoping that "all souls" may ultimately be saved. O My Jesus is a concise work of both popular theology and spiritual writing not unlike the kinds of interpretive commentaries on key prayers produced by Christian theologians since at least the third century.