DeHaan knew who Yacoub was the moment he saw him. He belonged to a certain tribe, native to the port cities, to Penang and Salonika, to Havana and Dar es Salaam. It was a tribe of young men, young men of humble origin who, with only their wits to help them, meant to rise in the world, and, to that end, had obtained a suit. They wore it all day, every day, and, because they were rarely the original owner, worked hard to keep it looking the best it could. Next, with help from an old book or an old man, they taught themselves a foreign language, maybe two or three, and practiced at every opportunity. Then, at last, to go with the suit and the language, they learned to smile. How glad they were to see you! What did you need? Where did you want to go?
This is one of a series of spy novels set in Europe in the runup to World War II