A compelling story from World War Two's U-boat war

My friend Lucy and I have been exchanging reading material over our summer birthdays for maybe 20 years. This year the top of my list was this one:

It focuses on the Wrens, a group of young women tasked with figuring out a strategy to keep German U-Boats from starving Britain into submission.

A quote from the book:

In December 1939, researchers from the University of Cambridge had tested whether Britain could survive with only domestic food production if U-boats forced an end to all imports. After subjecting themselves to a tough regime of work and a minimal diet, the researchers and their volunteers found  that they could survive, while  noting a 'remarkable' increase in flatulence ..

Fuel and clothing were worse .... rationed by 1941.

The solution: a game. The idea was to give sea captains the same look at the battle space they might get at the helm of their ships:

The game helped Britain come up with anti-U-boat tactics that turned the tide and kept the essential convoy goods coming throughout the war.

This is my favorite nonfiction read of 2020 so far. Five stars!