Knowledge and Christian Belief. By Alvin Plantinga. Grand Rapids, Mich.: Eerdmans Publishing, 2015. vii + 129 pp. $16.00 (paper).The Hiddenness Argument: Philosophy's New Challenge to Belief in God. By J. L. Schellenberg. Oxford: Oxford University Press, 2015. vii + 142 pp. $35.00 (cloth).Both of the books under review present important arguments for a broader audience that the authors had previously made in a more technical manner for professional philosophers. Plantingas also summarizes a long, distinguished, and provocative contribution to epistemology and thus requires more background to appreciate fully, so the treatments are unequal in length but I hope equal in illumination.For the past fifty years-ever since the publication of his first book God and Other Minds in 1967-Alvin Plantinga has been considered one of the most influential philosophers of religion in the world.1 Bom in Ann Arbor, Michigan in 1932 of Dutch parents and brought up in the Christian Church, Plantinga taught at Wayne State University, Calvin College, and the University of Notre Dame until his retirement in 2010. In the first of several volumes published over the past few decades engaging critically with various aspects of his thought, the editors write: Besides his landmark work in the philosophy of religion, Plantinga has authored many penetrating and beautifully crafted studies in metaphysics, epistemology, and the philosophy of mind. In particular, his writings in the area of metaphysics concerned with necessity, possibility, essence and accident are of profound significance.2Beginning in the mid-1980s, however, Plantinga's primary research focus began to shift from metaphysics to epistemology-both in regard to the general theory of knowledge and the rationality of religious belief. Against the common objection that belief in God is only rational if supported by valid philosophical arguments, the main assertion of Plantinga's Reformed Epistemology is that belief in God is in fact properly basic-that is, entirely rational whether any arguments support it or not.3 Such proper basicality is not unique to religious belief but also holds for memory, sense perception, and a priori beliefs regarding logical or mathematical truths. Plantinga thus argues not simply against the evidentialist objection to belief in God but against the broader epistemological framework in which it belongs, namely the classical foundationalism derived from Descartes and Locke. Along with his colleague Nicholas Wolterstorff, Plantinga was thus a signal voice in directing our attention away from exclusive concern about the validity or invalidity of specific theistic arguments to meta-epistemology, and thus to a deeper awareness that there is more than one way in which we can (and should) think about our intellectual obligations, assumptions, and capacities.In 1993 Plantinga published two substantial contributions to the general theory of knowledge, Warrant: The Current Debate and Warrant and Proper Function, which were then followed in 2000 by a massive, five-hundred-page magnum opus, Warranted Christian Belief, in which he sought to synthesize his broader epistemological concerns with his religious convictions.4 Indeed, he says that Warranted Christian Belief serves simultaneously as the third volume in his Warrant trilogy and as a sequel to God and Other Minds and his classic essay Reason and Belief in God.5 As the common element in the title of all three volumes indicates, Plantingas distinctive concern is not with the more familiar epistemological category of justification (which he believes is inevitably and unhelpfully limited to concerns about intellectual obligations) but with warrant, which he defines as the elusive further quality or quantity which, or enough of which, stands between knowledge and mere true belief.6 That is, what must be added to a given instance of true belief in order for it to constitute actual knowledge? …