The history of acoustical imaging is outlined by reference to seven topics. These topics relate in rough chronological order to the developement of various imaging systems and the development and application of optical theory to them. Some commentary is made on the influence of technological developments in other fields and their influence on acoustical imaging. The treatment is not exhaustive because of space limitations; there are more than 20,000 pages of literature on the subject and this is to be summarized in eight. An attempt has been made to present some of the major activity in the field over the last sixty yeras.