Maps are perpetually fascinating. Ostensibly their purpose is to clarify, but to anyone with a grain of imagination they are a source of wonder. Who has not, at one time or another, placed a finger on a page and asked themselves: what is it like there? It need not even be somewhere exotic. To aficionados of cartography the words ‘Old Gasworks’ have almost the same allure as ‘Here Be Dragons’. The same spirit of enquiry underpins Edward Brooke-Hitching’s excellent book The Phantom Atlas. But with one important difference: here it is not the reader whose imagination wanders but that of the map makers themselves.