A review by emerywebster
The Inner Game of Tennis: The Classic Guide to the Mental Side of Peak Performance by W. Timothy Gallwey

3.0

Introduces the concept of a self1 (thinker) and self2 (doer) where self1 mostly gets in the way of self2.

Seems eyerollworthy at first but includes some solid insights around practice and performance (esp under pressure) for basically any activity.