Kimball's book has appeal to both those within traditional and emerging church generations. For traditionals, he suggests that those trapped within "the Christian bubble" (having none other than only Christian friends) need to escape those constraints and begin building relationships with non-Christians--and do more listening than talking.
When he did that, himself a pastor of a church, he found the answers to his questions about Jesus and the church shocking. Non-Christians are quite willing to talk about Jesus and spirituality, but are largely turned off by the organized church.
For emerging generations, the book may bring about the realization that Chrisians today have an uphill climb in terms of sharing their faith with non-Christians, thanks to the (often negative) influences of traditional, organized churches. The real question becomes: How can Christians today share their faith in Jesus while at the same time honestly acknowledging the negative impact of organized religion, which is seen as part and parcel of the message about Jesus?
Offering more examples than necessarily answers, Kimball's book is a challenging read that is well worth the exploration.