A fantastic book that brings together research on “flow” states to craft a story (and actionable suggestions) on how we can all become happier with work and life.
I continue referring back to this book, and it blends well with many other books, like Deep Work, or Mastery. Heavily cited by other authors, it will force you to think about how you structure your life and the activities you pursue. Flow explains why we seek happiness in externals and what’s wrong with it, where you can really find enjoyment in life, and how you can truly become happy by creating your own meaning of life.

An individual who can control their mental space i.e. their ability to focus on a singular task without the proportion of external or internal distractions in the mind of a disciplined man. This ability to remain focused can be conditioned with meditation and mindfulness but is important to induce a flow-like state.