Xanthe Schneider is an agent with British Intelligence.
The period of time for which she works for that organization is the Second World War. Her connection to it comes largely from her very impressive abilities with puzzles. In her case it started with crossword puzzles as a girl growing up in Ohio. She was a whiz at them. And she had acquired her skills with languages from her father and was reading Kant in the original German long before she graduated high school. Her intelligence and drive would take her to Cambridge in England almost two years before we meet her in 1939. And her time at Simonetta College would be the impetus that would find her, an American, invited to work at Bletchley Park once the War with Germany began.
A passage early in her recorded adventures says a lot about both her and those adventures. After recalling how her father used to put her to bed with a "Sleep tight. Don't let the mice bite" and her frequent asking about where were the mice, we read: "There were stages in her life when she lived in such fear of the mice, with their little toes. It was only in her early twenties, in war-torn Europe, that she found there were bigger fears, and more terrifying ones, and she finally stopped worrying about the mice. In fact, there have been times when the thought of the mice in Cincinnati were actually comforting."
Schneider is a woman who, even if she might say otherwise, enjoys adventure. She would never have followed her father's wishes and left Ohio to travel alone across the ocean to go to college there if she did not have an urge for something different. This is largely why even as she begins to work at Bletchley, she will be almost searching for more adventure than just sitting in an office.