In the box in the middle of the first page of "Armageddon - 2419 A.D." by Philip Francis Nowlan, is written: "We prophecy [sic] that this story will become more valuable as years go by." I'd normally categorize a statement like that as hyperbole, but considering this story is the basis for the BUCK ROGERS comic strip, and resulting licensing that went on for decades after its publication; that it virtually defined 'rocketships' and space travel to the public until those things became fact, I'd say it was an accurate prophecy.
This is the link to an article on Buck Rogers' fiftieth anniversary from STARLOG, 1979:
"Armageddon - 2419 A.D." from AMAZING STORIES, August, 1928. Cover and illustrations by Frank R. Paul.