The distinguished German scientist, Hermann von Helmholtz, and the superb French writer, Marcel Proust, never met. However, Henning Schmidgen's fascinating study of nineteenth century graphic machines, tracings, and early photography reveals how their shared preoccupation with the physiology and mechanics of muscles and nerves, however disparate, led them to remarkably similar discoveries about the arbitrary and unpredictable modern experience of time.––-Anson Rabinbach, Princeton University, author of The Human Motor