K0SM0S

Stoicism is by far the best philosophy I've ever encountered.

this book helps understanding that living in the present moment is critically important, and a key to happiness.

I found The Obstacle is the Way by Ryan Holiday to be a very good introduction to Stoicism.

It's as short as it is good for the mind, the building/making of one's persona. Well worth a read at least once in your life

Psycho-Cybernetics, A New Way to Get More Living Out of Life (1960) by Dr Maxwell Maltz, MD.