The 1600s: the decade of Shakespeare’s Hamlet and King Lear, and of Caravaggio's radically dark altarpieces; the years when Galileo started launching a scientific revolution. All of them scratching at an urgent anxiety: how does reality hold together, once the old classical world systems have fallen apart? What, in other words, is 'nature'?

Julian Bell’s new book, Natural Light, introduces us to Adam Elsheimer (1578–1610),     a young artist from Frankfurt who frequented the same streets of Rome stalked by Caravaggio. Brooding on those pressing far-reaching questions, Elsheimer created intense and mysterious compositions on tiny copper panels. His art – later to become something of a cult secret – prompted others to rethink what 'the light of nature' might mean. Small as they were, his pictorial inventions touched the imaginations not only of his friend Peter Paul Rubens, but of painters as unalike as Rembrandt and Claude Lorrain. Even in India, the Mughal artist Payag would originate his own responses to these strange new visions of humanity and its footing in the world.