Destination Casablanca is about Operation Torch, the Allied operation in 1942 to invade French Morocco and Algeria; this allowed the Allies to gain an operational toe-hold in Africa to fight the Nazis from another side.
France held a weird position during WWII. The official French government was headed by Petain and collaborated with the Nazis: France was our enemy. But there were a LOT of dissenters – the decision to surrender to Germany in order to maintain a semblance of self-control was not unified by any means. A lot of army officers who didn’t necessarily agree with that decision were posted to France’s colonies – including Algeria and French Morocco. Which meant that a fair number of the officers in these two colonies were sympathetic to the Allied cause. A major part of Operation Torch was figuring out who they could trust and how much.
I also got to learn about Josephine Baker’s espionage career, which was a delight. She would smuggle messages on sheet music.
I would recommend Destination Casablanca, but be forewarned that the actual chapters on the battle sometimes get bogged down in detail.