In 1981, the SEG Executive Committee, after the matter had been discussed by several predecessors, approved publication of a journal to complement Geophysics, SEG's peer-reviewed archival journal which had been in existence since 1936. It is interesting that the leaderships of two major sister societies, AAPG and EAGE (then EAEG), came to similar decisions almost simultaneously. The Explorer, The Leading Edge, and First Break were all launched within a few months of each other. The first issue of The Leading Edge appeared in June 1982. Some pretty simple arithmetic concludes that TLE is starting its fourth decade with this issue and that is the obvious reason for this special section.