Paul Crane is an unwilling agent for the CIA.
Little is said about the early life of Paul Crane, probably because it was quite ordinary. He was a bright student, enough to have skipped the 3rd grade. He did very well in college, attending the University of Seattle and obtaining an engineering degree.
After college, he got a job with Boeing that lasted for several years until, apparently tired of the coat-and-tie world, he quit that huge corporation and became a free-lance engineer, sometimes working for Boeing. Working for the CIA was never one of his plans but, as the series opens, he isn't given much choice.
He is unattached, except for his cat, Tiger. He is young enough to be able to talk somewhat coherently with the young crowd but is old enough to be let into the adult camp. His attitude towards the Agency is not very good, understandable since he was coerced into working with/for them, but his attitudes towards the repressive regime of Communist China is far less. His work, while begrudgingly, is still strong and determined. To modify an old adage, "the enemy of my enemy is an even bigger jerk" seems to be Crane's attitude throughout both books.
When first published, these books were released under the pseudonym of Wade Curtis and it was only after the author's success with his real name in the science fiction genre that they were re-released as by Mr. Pournelle. Shortly after the second book came out, the first of many terrific science fiction novels came out, especially in 1974 when he teamed with Larry Niven to create several absolutely incredible adventures.