What is the theme in The Cross and the Switchblade by David Wilkerson?

The power of Christian faith is the main theme of the book. As discussed in "Style - Perspective" and "Tone," there is the very clear sense that the author has written this book with the intent of inspiring both Christians and non-Christians with the power of Christian faith. Time and again, he portrays himself and those with whom he works and lives as being defined and/or changed by the power of deep, fervent, spoken prayer to the Christian God. Time and again, he portrays the (often desperate) circumstances in which he finds himself as being positively resolved by trusting, faithful, detail-specific communication with that same God. Time and again, he refers to the power of Christ and of the Holy Spirit,