In this critical examination of Descartes's "Fourth Meditation" and the latter part of the "Sixth Meditation", Joel Thomas Tierno has produced not only an interesting contribution to Cartesian scholarship, but also a groundbreaking work in theodicy. Each of the theodicean problems that Descartes examines is developed in detail. So are his various arguments with respect to the compatibility of these forms of error and God's infinite perfection. As a part of this process, the significance of the problem Descartes raised in the "Fourth Meditation" to his larger epistemological project in the Meditations is carefully considered. This relation has not previously been adequately appreciated or investigated. The distinctive feature of Tierno's arguments is that his conclusions are drawn from the failure of Descartes's arguments in the "Fourth Meditation". Tierno implies that these arguments are crucial to Descartes's philosophical project as a whole and, as such, deserve greater attention.