Face value. An A - Z of selfies, mugshots & the contemporary

Jessica Helfand is a designer, artist, and author of "Face: A Visual Odyssey", an elaborately illustrated A to Z showing how our faces have been perceived, represented and judged over time from anthropometry and eugenics to surveillance. Educated at Yale University, where she has taught for more than twenty years, she is a co-founder of Design Observer and the author of numerous books on visual and cultural criticism. Kathryn Ryan talks to her about her sprawling history of the cultural significance of the face.