When examining how our bodies work, we are all aware of the circulation of the blood or the fact that cells can misbehave and cause cancer. But how many of us are aware of the important role played by electricity?

Frances Ashcroft, a professor of physi-ology at Oxford University, is a distinguished scientist. As this compelling and very readable book shows, she is also an excellent writer. One of her major achievements came as a breakthrough late at night some twenty-four years ago, when she discovered a channel in the membrane of a beta cell of the pancreas that regulates its electrical activity and causes insulin secretion. Her surprising discovery led to a treatment with pills for those rare cases of babies born with diabetes. It also inspired in her a fascination with the electrical activity of cells. 

Channels in the membranes of our cells, through which tiny ions move, dominate our lives. About one-third of all our energy from the food we eat is used by our cells to pump out sodium. This is necessary to prevent water from entering cells by osmosis and making them swell