It enabled us to walk out of Africa and to spread as far as Alaska and Australia. It freed our hands and freed our minds. We put one foot in front of the other without thinking - yet how many of us know how we do that, or appreciate the advantages it gives us? In this hymn to walking, neuroscientist Shane O'Mara invites us to marvel at the benefits it confers on our bodies and minds, and urges us to appreciate - and exercise - our miraculous ability.