The making of pictures has a history going back perhaps 100,000 years to an African shell used as a paint palette. Two-thirds of it is irrevocably lost, since the earliest images known to us are from about 40,000 years ago. But what a 40,000 years, explored here by David Hockney and Martin Gayford in a brilliantly original book. They privilege no medium, or period, or style, but instead, in 16 chapters, discuss how and why pictures have been made,...