The Unseen Presence, by Mel Goebel
The Unseen Presence is a moving story of Mel Goebel's troubled upbringing and how Christ rescued him. Mel became involved in drugs and alcohol at an early age, and found himself in prison at 20 years old. The turning point in Mel's life was when he met another prisoner whom he referred to as a "Jesus freak." After skeptically questioning this "Jesus freak," Mel was challenged to read the Bible himself. Through reading a Bible borrowed from a chaplain he learned of salvation, and turned to Christ.
The Unseen Presence describes the ministry God provided Mel after his salvation. Having a burden for other prisoners Mel began to work with Prison Fellowship, where he was able to have a gospel impact in prisons. He is now the president and founder of Life Relaunch, a men's ministry which seeks to "restore men's hearts, renew their minds and commission them as warriors to love Jesus and advance His kingdom."
The Unseen Presence is an inspiring story, showing how God drastically changed a man's life and used him to impact the lives of others.
It's a 2001 copywrite, but you can likely find a used copy on your favorite Amazon Smile website.