Concentration is the skill of undivided attention, the super power of committing our attention to what we want at a given time, and nothing else. When all our faculties converge in a single activity or direction, the mind and the body are happy. Our background worry programs often fade, and we can find ourselves in “flow” states of optimal performance. The opposite is having our minds pulled in a dozen discontinuous directions, forever finding and making new problems, never collected, never satisfied. The research is clear; to cite the title of one famous paper, “A Wandering Mind is an Unhappy Mind.” Over time, concentration leads to more stability and peace in the rest of life. Somehow, the flow flows out. For this reason, concentration is the foundation of many meditation practices.