Transit Maps of the World by Mark Ovenden: Book #18 for 2016
This book contains a comprehensive collection of maps showing public transport systems from around the world, along with commentaries.
I have a fascination with maps of urban transit systems, mostly stemming from my obsession with London's underground system, so I loved this book. It had some fascinating facts about transport in cities all over the world, though I was mainly interested in the maps themselves, with some that were more interesting than others (inevitably, the more detailed and complex ones). My only real complaint was that some of the maps seemed very small and difficult to read.