I am just about through with this book.  The author, an atheist, sold "his soul" on ebay, to go to the church or temple of whatever choice the high bidder wanted for a period of several months.  A Christian paid the high bid, and told him to visit at least 15 churches and report on them.  This book is the result.  It is a very interesting report on quite a number of churches, with specific references to the churches, messages, pastors, ushers, music, etc. as seen through the eyes of an unbeliever.  It is instructive in many ways to those who are trying to reach out to unbelievers.  I hope to finish the book in May 2009.