If you're like me, and enjoy poring over maps, you'll find this book a treat. If all the book had were reproductions of current urban rail maps, it would be worth at least 4 stars. But there's much more. There is a short history of urban rail from its earliest days, and then you have maps and text for about 200 cities around the world. You get narratives on the history of each system, but the emphasis is on the evolution of the transit maps themselves. For some cities, up to about 20 maps are reproduced, and some of these date back to the 19th century. There's a wonderful sense of the conflict between having maps that are aesthetically pleasing and maps that are pleasing to someone trying to find their way around.
The book is divided into 6 zones (rather than chapters), with the distinction based primarily on the evolution of the maps:
zone 1: 8 cities, 4 pages per city. Example: Paris, 17 maps dating back to 1900.
zone 2: 15 cities, 2 pages per city. Example: Boston, 5 maps dating back to 1926.
zone 3: 28 cities, 1 page per city. Amsterdam, 4 maps.
zone 4: 16 cities, 2 cities per page, usually 1-2 maps per city.
zone 5: 18 cities, 1-3 cities per page, mostly 1 map per city.
zone 6: 140? cities, about 12 cities per page, often without maps, very short narratives.
The one problem you'll have is that many of the original maps were very large, and so when the transit map of Greater New York is faithfully reduced to two-thirds of a page in the book, you'll either need remarkable eyesight or a very strong magnifying glass to make out details. But the book is not intended as a catch-all way to actually find your way around, but rather as a paean to maps--you're intended to enjoy looking at the maps, not using them for transit purposes. A real delight!