The new map is the latest in a long line in attractively packaged, specialist maps from Blue Crow Media which highlight the locations of a single feature of London on a bepoke basemap and guide – be it notable trees, Brutalist buildings or in this case, alleyways. The maps is folded into A5, held in place with a paper “slip”. Unfolding reveals, on one side an A2 basemap of central London – stretching from Marble Arch to Hoxton, and Camden Town to Borough, in shades of blues, greys and greens, with London Underground stations highlighed and captioned on top in white. Superimposed with orange lines, are the alleyways that are the purpose of the map. These are focused around the City of London and the riverside part of Westminster in particular – these areas being the oldest parts of London, alleyways developed organically before the wider roads needed for horses and later cars and buses. Some notable alleyways further away are also included. On the other side of the map is a guide to the alleyways, including a description (and grid reference) for each one, often accompanied with a photograph. Some of the more famous alleyways included in the guide include Wallside (one of the famous Barbican Highwalks), Wine Office Court (home to the properly ancient Ye Olde Cheshire Cheese pub) and St Dunstan’s Alley which crosses behind one of the City of London’s most beautiful open spaces. There’s a couple of surprising omissions – I expected to see Leake Street, the well-known Waterloo graffiti corridor, and there is only one alleyway south of the River Thames included – so no Clink Street or any of the under-bridge passages. But over 50 are on the map, including several your reviewer had never heard of,...