The London Transport bar and circle – also known as the bulls-eye or roundel – is an icon of commercial design. Over the last century it has come to represent not only London's transport network but also the city itself. Rare for the logo of a large organization, the symbol is often perceived as being 'cool', and its influence has extended into many other fields, including fashion, pop music and counter-culture.

This fascinating book charts the history and development of the symbol from the early 20th century to the present day, and explores its use across the company's many activities, as well as its wide-ranging cultural influence. Richly illustrated with poster artworks, photographs and other graphic material from the London Transport Museum archives, the book features numerous inventive uses of the logo, many of them previously unpublished.