Every second throughout life, billions of sodium-potassium pumps enable the human muscle cells to function. The pump is an enzyme found in the plasma membrane of all animal cells and is an important example of active transport. The Na+, K+-pumps keep us going by pumping sodium out of cells while pumping potassium into cells and without them, we would not survive. Addressed to specialists in the field of biomedicine, the author presents a thorough overview of his scientific results over more than 40 years. The book is richly illustrated and seeks to explain how a single molecule creates the required conditions for our muscles to work.