Found in 3 comments on Hacker News
This is a good one to - "The Thinker's Toolkit: 14 Powerful Techniques for Problem Solving" by Morgan D. Jones, ( techniques as used by the CIA no less! :-) ).

https://www.amazon.com/Thinkers-Toolkit-Powerful-Techniques-...

bensochar · 2017-11-20 · Original thread
One of the books I still reread. Its not so much about "abstract thinking" but its very good at teaching you to find the real problem & make a decisions. https://www.amazon.com/Thinkers-Toolkit-Powerful-Techniques-...
nerfhammer · 2010-08-26 · Original thread
mass market book by one of his colleagues: http://www.amazon.com/Thinkers-Toolkit-Powerful-Techniques-P...

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