Many scientists in the past have devoted time and thought to the origin of lunar craters; three deserve special attention for their imaginative ideas and original experiments. Robert Hooke, in seventeenth-century England, devised experiments to produce model craters, and he proposed impact and “gas bubble” hypotheses to explain crater origins, introducing ideas of long-lasting influence. The work on lunar craters by the distinguished nineteenth-century American geologist G. K. Gilbert led him to a hypothesis for the origin of the Moon, introducing ideas that have only recently received supporting evidence. Finally, Alfred Wegener, the German meteorologist best known for his development of the hypothesis of continental drift, performed a series of excellent experiments to support the impact origin for lunar craters and also for the terrestrial Meteor Crater.