FOR OVER A CENTURY, THE LONDON UNDERGROUND ROUNDEL HAS GOTTEN INTO THE DNA OF SOME OF THE WORLD'S TOP DESIGNERS. A NEW BOOK EXPLORES HOW. It is hard to imagine a simpler symbol than the one that brands every London bus, subway, and station, the London Underground Roundel. Although little more than a dark blue bar placed across two red-rimmed semi-circles, the Roundel has evolved from humble signage meant to tell passengers where to get off the train to an emblem that represents not just a metropolis but its people as well. The Roundel's incredible journey is being freshly explored in Logo for London, a beautiful, lavishly illustrated new book. Published by Laurence King, Logo for London tracks the Roundel's cultural, artistic, and social importance over the last hundred years as it became the world's most well-known transportation symbol. "Like many millions of other people commuting through London, I saw this symbol at...