What is the theme in The World's Religions by Huston Smith?

Not surprisingly God and Religion make up the main theme of this book. Throughout the book, an emphasis is placed on the nature of God and the different ways God is seen through the eyes of the various religions of the world. In some instances, such as Buddhism, the concept of God is non-existent; whereas in others, he is the creator of man and the universe. In Judaism, Islam, and Christianity, the concept of God is strikingly similar.