A few months ago a colleague loaned me a copy of Mr. Beck's Underground Map. It is a richly illustrated book on the development of the London Underground map, something that is now considered a classic in design. A great online companion to this book is Owen's Massey's Mapper's delight:The London Underground diagrams. It provides links and descriptive text to a number of sites that show different versions of the London Underground map as well as other attempts at mapping the Underground. Of particular interest to cartographers are the maps of the actual geographic layout of the system. Compare this to the Beck-designed map.