 Classical, alternative versions of the ontological argument are propounded by Anselm, Spinoza, and Descartes, with current versions by Alvin Plantinga, Charles Hartshorne, Norman Malcolm, and C. Dore; classical critics include Gaunilo and Kant, and current critics are many, including William Rowe, J. Barnes, G. Oppy, and J. L. Mackie. The latest book-length treatments of the ontological argument are two defenses: Rethinking the Ontological Argument by Daniel Dombrowski (2006) and Yujin Nagasawa’s Maximal God; A New Defence of Perfect Being Theism (2017). Not every advocate of perfect being theology embraces the ontological argument. Famously Thomas Aquinas did not accept the ontological argument. Alvin Plantinga, who is one of the philosophers responsible for the revival of interest in the ontological argument, contends that while he, personally, takes the argument to be sound (because he believes that the conclusion that God exists necessarily is true, which entails that the premise, that it is possible that God exists necessarily is true) he does not think the argument has sufficient force to convince an atheist (Plantinga 1974: 216–217).