Note also that around 1972 and 1973, DC was putting out a lot of regular price books with all reprints--maybe to keep up with Marvel who were flooding the racks with such titles. So DC brought back books like DOOM PATROL, INFERIOR 5, CHALLENGERS OF THE UNKNOWN, but only for a few reprint issues. However, CHALLENGERS OF THE UNKNOWN did come back again in 1977/78 for six more issues of new material.