What book or paper have you found adds value to your understanding and practice of Design thinking, Lean, and Agile

I still find this free book useful as a way fo understanding how they fit together.
http://jonnyschneider.com/free-book

I like that it does a bit of work to link how these concepts to link together to form a way of working and acting to achieve goals.

Also very interested to rethink my ideas. So if you feel that design thinking, lean, and agile are not great and are the old ways. Please tell us what works better for you now.

Cheers Bruce