50 Reasons People Give for Believing in God Harrison, G.P. Prometheus Books (June 5, 2008)
This is a great book for people first beginning to question belief in God and wanting to familiarize themselves with the arguments that are available. It does not present complex philosophical or scientific arguments that will alienate its readers, nor does it take a combative tone. Rather, it is conversational in nature and based very much on common-sense.
The organization of the book is its strength. Each chapter title is a common statement made by religious people to justify their beliefs, and the chapter then goes on to respond to these statements in a logical, respectable, often humorous, and easy to read manner. The chapters are fairly short and easy to understand, and each ends with a bibliography for further reading.
I feel this book is a great introduction and stepping-stone into some further, more complicated texts. Other books may be too harsh for someone who is just beginning to inquire about this subject and may alienate readers.