The fifty years from 1930 to 1980 almost completely cover the entire history of the reflection seismograph exploration industry. During its growth from infancy to maturity there have been many major technological breakthroughs and innumerable evolutionary advances. At the conclusion of any time period, there is a tendency to believe that the peak has been reached, only to see significant breakthroughs which start a whole new round of amazing developments. So it is today with a veritable explosion of channel capacity in the recording systems and three-dimensional surveys finally just becoming a practical reality. The prospects for major improvements in the resolving power of the seismic exploration method have probably never been better.