The capacity of our brain is limited. Everyone knows the feeling that after a long day, it is hard to concentrate, make difficult decisions, or empathize with others. We live in a chronically exhausted society. For years, the capacity of our mental battery has been shrinking. Lack of exercise, poor nutrition, harmful substances in the environment, lack of or harmful social interaction, and constant digital noise lead us to live in a way that is not in accordance with our nature, which further diminishes the performance of our brain. Dr. Michael Nehls embarks on a quest to find the source of our mental energy and succeeds. He reveals for the first time where our "brain battery" is located, what function it serves within our brain, and what this means for our thinking. Dr. Nehls describes the dire consequences of a shrinking mental battery for us, our society, and future generations, as well as how we can counteract this trend.