This is by far the single most helpful book on sexual purity for men that I’m aware of:
Heath Lambert. Finally Free: Fighting for Purity with the Power of Grace. Grand Rapids: Zondervan, 2013. 176 pp. 23-page sample PDF.
It’s clear, direct, practical, and grace-giving.
I highly recommended this for men who are fighting lust or wallowing in it. I pray that God will use this book to help thousands of men be “finally free.”