What is the author's style in Whoever Fights Monsters by Robert K. Ressler?

Whoever Fights Monsters is written from the perspective of Robert Ressler, the author and chief subject of the book. Because he is also the author, Ressler's book has the feel of a professional autobiography or memoir. Of course, most of Ressler's life is not discussed. The reader learns almost nothing about his wife and children or anything else personal about the man. What one does learn about is his chief passion and work, studying and interviewing serial killers. Because Ressler has a lot of experience and opinions on these men, it is clear that readers are getting his account of the story. In at least one case, that of Duane Samples, the killer and several other people actively disagreed with Ressler's account. Needless to say, Ressler takes the point of view that he is correct and Samples is wrong. It is worth taking this personalized perspective into account when reading Whoever Fights Monsters. It is not that one cannot trust Ressler, but one needs to recognize that he has a distinct point of view that may, at least sometimes, be coloring his accounts. Still, given what one has learned from Ressler in other parts of the book, the reader is inclined to trust him. Most of the facts of the cases are a matter or public record and Ressler has no reason to lie. He also goes to great pains throughout the book the highlight the importance of profiling while downplaying the role of the actual profilers, specifically himself.