I'd give this one a 3.5. Although the author repeats himself occasionally and can sometimes seem a bit overly proud of his accomplishments, it is fascinating to be provided with such an insider's view on the function and responsibilities of the Drug Enforcement Administration. It's clear that Jack Riley, who rose to the place of second in command in the DEA, was a dedicated special agent and easy to see how someone like him could become obsessed about bringing El Chapo Guzman to justice. Not only did this man make billions from drug trafficking, but he and his minions were responsible for the deaths of many. As Riley describes his rise through the ranks of the DEA, he regales readers with stories of his work in Chicago, Washington, DC, St. Louis, and El Paso as different drugs became popular and opioids began to take a toll on many families. Although I wish that he'd have provided more details and more of his own solutions to what seems to have become an epidemic--51,000 individuals in the United States died of an overdose in 2018, he says--in many ways this book provides some historical perspective on the war on drugs and why it has been so unsuccessful. Many of the changes he made in the DEA are common sense, resulting in cooperation across agencies. It was fitting that he chose to retire after El Chapo, the man he sought for so long, was finally caught and brought to the United States. While the chase after El Chapo is intriguing as well as frustrating, I wish that the author had provided additional anecdotes from some of his other assignments. While he might be a little bit full of himself, perhaps it's justified when considering his accomplishments and exploits. This book certainly held my interest all the way through and made me understand more about opioids, heroin, and fentanyl. All those in law enforcement should read this book to be inspired by a very good cop and to learn from his methods. The rest of us should read it and then feel grateful that men such as Jack Riley are on the case.