I am patiently awaiting the release of the first book about DET-A Berlin:

https://www.amazon.com/Special-Force...dp/161200444X/

I'm hoping it will provide some insight into how the Cold War was fought in Eastern Europe and how the Baltic States could be defended moving forward.

Until then, and while I'm focused on the Hacking 4 Defense Educator's Course starting here in Washington DC:

Influence: The Psychology of Persuasion

....highly recommended and only $1.99 right now on Kindle. Awesome value.

https://www.amazon.com/Influence-Psy...dp/B002BD2UUC/

Sprint: How to Solve Big Problems and Test New Ideas in Just 5 Days:

https://www.amazon.com/Sprint-Solve-...dp/B010MH1DAQ/

The Lean StartUp:

https://www.amazon.com/Lean-Startup-...dp/B004J4XGN6/

Thinking Fast And Slow:

https://www.amazon.com/Thinking-Fast...dp/B00555X8OA/

Steal Like an Artist:

https://www.amazon.com/Steal-Like-Ar...dp/B0074QGGK6/

Everything by Dr Tina Seelig(creativity & innovation):

Innovation Engine (Enhanced Edition with video & audio): A Crash Course on Creativity is only $6.99

https://www.amazon.com/Tina%20Seelig...rnid=618072011

I buy tons of books. These are some of the very best I've found in recent years on creativity, innovation, and problem solving.