This is a full ebook which puts the traditional Catholic proofs of God's existence into a modern context. It covers most of the arguments raging in the theism v atheism debate and also includes quotes on the nature of God and his existence from c.80 philosophers and scientists.
(To clarify for the benefit of a reviewer below: you need to access the menu for this app by pressing the menu button on your device's hardware. There you will see a table of contents etc which will allow you to navigate the app. Don't forget to be patient as it moves through the contents, it will be slow because there is a book sized amount of text here, not just a few articles.)