Book excerpt: To communicate, people have always used signs and symbols: marks, gestures, and words that represent abstract ideas and concrete objects. Over time, these have multiplied into an immense and complex network of images, figures, emblems. We use signs to measure such difficult concepts as number, danger, value, distances in time and space, and even love. How does a sign represent the thing for which it substitutes? How do we come to understand the meaning of a written symbol? What happens when a sign crosses international borders of language and culture? Chapter by chapter, Georges Jean conducts us through the fascinating realm of maps, pictograms, logographs, letterforms, patterns, signals, codes, and facial expressions.