Swinburne's book adopts the strategy of defending theism as the best explanation for a wide range of phenomena. By doing so, Swinburne brings to the philosophy of religion a new and innovative epistemology, one which focuses on the importance explanation plays in our quest for knowledge. As a result, his defense of theism is clearly the best out there. Much of _The Existence of God_ is devoted to the topic of explanation, making this book a key text not only for those working in philosophy of religion but in epistemology and philosophy of science as well. Swinburne's methodology is, I think, clearly on the right track; and as a result there is little doubt that his arguments for theism are powerful and deserve serious consideration.
I do not, however, find Swinburne's defense of theism to be successful. Swinburne focuses too much on simplicity as what determines the best explanation. If we take into consideration other elements of good explanations, such as explanatory depth, Swinburne may not be able to make many of the arguments he does. Also, many of Swinburne's arguments are based on what God has *reasons* to bring about; a consideration which may simply beg the question against the atheist. Swinburne's main critic, J.L. Mackie, says nothing about explanation in his response, _The Miracle of Theism_, and thus lets Swinburne get away without being challenged at the heart of his defense.
However, despite its flaws, Swinburne's book is the most powerful use to date of the new explanationist methodology applied to the question of God's existence. No one interested in this issue can afford to pass this work up.