I say that the book is incredibly well put and really sticks to the thriller that it proclaims to project. The characters in the book had no slack or delay in their actions that weren't supposed to be present during intense scenes. Better yet, I adored the professionalism that the main character, Cavanaugh, had portrayed to show his mantra of being invisible, covering every aspect of footprints that might've been marked from every phone call answered to where to even place their garbage. Every word and action just led to the excitement that led me to the end of each chapter to see Prescott, the antagonist, finally get what he deserved. Additionally, I sensed the battle of intellect between the two; a professional scientist that everyone wants, and an elite agent, who managed to find the other through aspects not many would think to look.
In the prologue, the author did mention having some of the information in the book be from colleges from the military, navy seals, and other factions that supported the usage of the materials retrieved by Cavanaugh throughout the book, like the tactical usages of duct tape, the benefits of an Emerson Close Quarters Combat (CQC) -7 knife, making a silencer with a milk container, and, the most intriguing of them all, the detailed description of how to disappear. There were many more, but I was fond of these in particular. I enjoyed how Cavanaugh would purchase a random assortment of items and wouldn't explain the reason until during usage, which made it more exciting to see what was to come next as they were used in the most tactical of ways.
There was a minor dislike towards the book, however. Following the sequence of events, there was some small irony as to how the protagonist and antagonist meet face-to-face again. Emphasis, it didn't correlate with the professionalism and instructions both were supposed to set out for throughout the book to lead to the conclusion it was supposed to have. Examples would lead to spoilers, but the flow depicted a lack of character from the antagonist through bad decisions, which made it harder to want to finish the book when I was only several pages away from completion. Additionally, some of the information shared uses a lot of words most probably haven't heard of before or wouldn't need to process unless truly intending usage of a gun, which may cause some confusion while it tries to explain its parts and benefits.
The author's writing was definitely aided by experience which made the characters better to feel for. I think to make something like this would require an isolated yet arduous gradation of real military work with the perspective of one of the best soldiers. In all honestly, I know Cavanaugh would and has qualified, and I also know that the main character is often a small representation of its creator.
In conclusion, David Morrell is an excellent thriller and experienced writer for an audience that desires adventure and is willing to be witnessed to information often gained in a more sophisticated environment. However, I would recommend this for a mature audience as well, for there are some parts of the book that may be sensitive to those not used to envisioning death and weaponry in a complex way. But all together, it is a great access to information and storytelling with a plot that touches more of a psychological and scientific aspect.