At first, Mark Prothero, Defense Attorney for Gary Ridgway, thought: "This can't be the Green River Killer! He's too ordinary! He's too small. He's too calm. He's too polite! He can't possibly have murdered forty-nine women. They can't be serious! They must have screwed up! I didn't realize then, but I was right. Gary Ridgway hadn't killed forty-nine women. He'd killed even more than that."
Soon, Mark Prothero faced the question: "How could you possibly defend the most prolific serial killer in United States history, the infamous Green River Killer? If anyone deserved to be executed for his crimes, didn't he?"

Mark Prothero, co-lead defense attorney who helped save Gary Ridgway from the death sentence, has heard that question many times. Now he’s written a book that reveals the true, inside story of exactly how an idealistic public defender, high school swim coach, husband, and dad could bring himself to spend many months of close confinement with a man who brutally murdered at least 75 young women, often in the act of sex. Defending Gary shows how Prothero could reconcile these monstrous acts knowing the reality of this unassuming fellow Gary Ridgway, a mild-mannered, church-going, devoted husband, father, and former Navy man, with an IQ of around 82 and a longtime job as a truck painter from Auburn, Washington, near Seattle.