The wikipedia article [1] describes it pretty well. It's a fascinating concept and if you find it interesting I can highly recommend the book Flow: The Psycholo

The wikipedia article [1] describes it pretty well. It's a fascinating concept and if you find it interesting I can highly recommend the book Flow: The Psychology of Optimal Experience, by the guy who introduced the concept. Personally I'd say when it comes to happiness 'flow' is a bit too narrow a concept. Or rather, it's a specific form of 'wu-wei' ("natural action, or in other words, action that does not involve struggle or excessive effort"). A great book on wu-wei which also references the concept of flow is 'Trying Not To Try'. I can strongly recommend this book as well. Especially it's final chapter(s) provided a lot of food for thought. [1]: https://en.wikipedia.org/wiki/Flow_(psychology) https://en.wikipedia.org/wiki/Flow_(psychology)