There is no reason you actually need to know any of this. But I thought maybe, after reading this book, that you, like Leonardo, who one day put 'Describe the tongue of the woodpecker' on one of his to-do lists, would want to know. Just out of curiosity. Pure curiosity.

Leonardo's notebooks offer the most vivid record we have of a great mind at work, with all of its passions and quirks on display.