George Mueller is an agent with the CIA.
This is an Agency which is just a half decade old when these adventures, which take place in the early 50's, occur. The concerns affecting its members lie primarily in the concerns with the ever-expanding Communist threat. The Soviet Union had swallowed up a good chunk of Europe and was making overtures to North Africa. The Chinese communists had taken over that most populous country just a couple years before and Indochina was feeling the threat as well. The need for trained, intelligent, and dedicated operatives to fight these dangers was extremely high.
Mueller was one of those that answered the call and fit the requirements just mentioned. As we are told early on, he had grown up in the Midwest and then was admitted to Yale on a scholarship. He "left Yale early to fight against Hitler's Germany, caught up in the great patriotism that drove America's young men into the armed forces. Through friends of friends of earlier graduates, he found himself in Texas training for the OSS. He parachuted behind enemy lines to help French Resistance sabotage rail lines and then played a small but dangerous role in occupied Norway that earned him a Purple Heart. He completed his undergraduate degree after the war and through a series of happenstances - choices presented to him - he worked on Wall Street, became bored, drank, and was recruited by his friend Altman to join the urgent battle in Europe against the Soviet Union. Mueller wanted to believe that he could make a difference in the world."
Mueller is described as "just shy of six feet, and on the thin side, which made him appear lanky". "His face was slightly oval, hair parted on the left, and combed straight back, and he wore clear plastic eyeglasses that made him look inconspicuous, a man who could sit in a restaurant and not catch a waiter's eye."
He is/was married to an Austrian woman who worked for the CIA in the years after WWII as an interpreter and they have a son aged six who he very seldom sees since his transfer back to the States and the desire of his wife, Johana, to remain in Austria.
Mueller is nearing the end of his time with the Agency. It was stated that the politics his bosses were constantly playing and the internal wars, not to mention those with the other government agencies, were like a "daily grind" that he wanted to put behind him. "Each morning he got up to face the endless urgency of ambitious colleagues inventing useful crises. Politics had taken over everything. He was tired of the double life, the daily mask, and he'd lost his ability to appear interested in a conversation when he was bored out of his mind."