The giant impact hypothesis: past, present (and future?)

At the request of editors, this paper offers a historical review of early work on the giant impact hypothesis, as well as comments on new data. The author hereby claims (whether believable or not) that his interest is to move towards a correct model of lunar origin, not to defend a possibly incorrect idea, just because of being a co-author of a relevant early paper. Nonetheless, the 1974 giant impact hypothesis appears still to be viable.