Jonathan Brooks is a lawyer.
More specifically he is a maritime attorney, obviously one who specializes in cases dealing with events and problems happening on the high seas. A New Orleans lad all his life, which the delicious drawl tells everyone who happens to hear it, Brooks might travel elsewhere as his law practice necessitated, but he always returned to southern Louisiana as quickly as he could.
That is where we first encounter him and where for most of the adventures we have of him he will start out. He will be required to do some extensive traveling, though, and he will see how places like Washington, D.C. and Moscow are a whole lot different than the bayou area.
Lawyers do not, as a rule, have much dealings with the cloak and dagger world since the latter would prefer to handle their business in secret and attorneys, especially trial lawyers like Brooks often is like to have lots of things out in the open. Brooks will learn as the adventures get underway that he has to learn to adapt and learn quickly not only to succeed but also to just stay alive. There will be more than a couple of people and organizations who would not mind seeing Brooks very much dead.