I recently had finished the OCD workbook and I'm about halfway through "Tormenting Thoughts and Secret Rituals". It's a bit older (Late 90's), and it has much of the same information as the workbook, but it has a few extras (slightly more in depth discussions of specific cases) that I've found to be worth the time and money... it's nice to read about others with the same condition, how they were treated, and how they progressed and overcame.