Philip Carlo's successful and acclaimed books reveal the truth about notorious characters such as LA serial killer Richard Ramirez, Mafia contract killer Richard Kuklinski and crime-family boss Anthony Casso. Working closely with the DEA , Carlo also wrote the definitive account of Bonanno Mafia family assassin Tommy 'Karate' Pitera.

Carlo's investigative achievements were remarkable, but what wasn't known to his readers was that, while working on The Ice Man, he learned he had amyotrophic lateral sclerosis (ALS), a form of motor neuron disease. Suddenly, after years of penetrating the minds of killers, Carlo was himself being pursued by the grim reaper. But rather than lying down and succumbing to the disease, Carlo continued to work right up until his death in 2010.

In The Killer Within, Carlo provides an intimate account of his relationships with Ramirez, Kuklinski and Casso and reveals intriguing information about writing his bestsellers while simultaneously coping with ALS as it slowly began to steal his life away.