Color map of London subway system, on sheet 15.5x22.5, folded into 16x7.5. Designed by Hans Schleger. Beck's underground maps had been published since 1933. In 1938 Beck's design was altered by Hans Schleger, and this new design was published in 1938, 1939 and 1941. The map maintained all the elements of the Beck's circuit approach but with distinctive modification with blue-green background intended to highlight the central area. It shows early signs of zoning, and does not include the iconic Underground logo on the map.On verso: 4 maps showing the places of interest.