Hooke’s Micrographia is much more than a simple set of beautiful microscopic observations. For what really fascinated Hooke were the inner physical mechanisms by which nature worked. His work included experiments with light, from which he proposed that light was a “pulse” or wave. His insect studies were primarily concerned with how flies and moths flew as living machines, while Observation 60, where Hooke asked what forces formed the lunar craters, inaugurates the science of lunar geology. Part of the International Year of Light.