This is a book about maps and map-making, about power and class, and about war, seamanship and navigation. It is a study of wealth, patronage and money, in an England riven by religious disorder and toxic politics. Greenvile Collins (1643-94) was a naval warrant officer who caught the attention of a King. His seagoing career took him from Patagonia to the Arctic, into battles against Dutch men of war and Barbary corsairs, and to the slave markets and Silk Road ports of the Mediterranean. A scientific navigator, his professional drive drew him to Shetland, the Scilly Isles and all points in between, as he undertook the most ambitious hydrographic survey of the British coastline yet attempted. Then, even as he laboured to complete his monumental sea atlas, he was summoned yet again to the service of the Crown. The Glorious Revolution was a campaign of crisis for a deeply conflicted Royal Navy, and a crucial test of loyalty for Greenvile Collins and his fellow officers.