I got a review copy of Mark Ovenden's "Transit Maps of the World" in the mail today and promptly fell down the rabbit hole with it. The book does pretty much what you'd expect: shows you the maps for pretty much every transit system in the world, with some well-written commentary (history, trivia, graphic design challenges), including historical maps of the major transit systems as well as photos of some incidental artwork, like the stunning Deco covers the French put on the old Paris Metro maps.
This is sheer public transit/map porn, and I'm in love. The challenge of representing the geography and network logic of complex transit systems is a daunting one, and while many of the maps converge on solutions similar to the archetypal New York and London maps, others (like Tokyo and Hamburg) have sui generis solutions that are smart and unexpected.
This is the kind of book that would be incredibly fun to browse with kids as part of a world geography investigation — and also the sort of thing that makes great bedtime reading if you want to salt your dreams with the possibility of travel to distant cities.