Bizarrely, five out of the last seven American presidents have been left-handers, including Barack Obama. It is, admits Smits, a Dutch science journalist, an "improbable number". His history of handedness is a fascinating cornucopia of science and superstition. Surprisingly, scientists have still not fully explained why people are either left- or right-handed, or why there has always been a stable left-handed minority of about 10%. But Smits, who is himself left-handed, is understandably aggrieved by bad science that fuels prejudices against left-handers. As recently as 1961, the American psychiatrist Abram Blau warned parents: "Don't let your child be a leftie!" Smits neatly skewers many pseudo-scientific claims, including the myth of high mortality rates among left-handers. Sadly, prejudice against left-handedness is deep-rooted and universal. But although the Devil may have been a leftie, the left hand was also symbolic of life itself. Michelangelo, who was ambidextrous, depicted Adam receiving life from God through his left index finger.