|(1) A project first suggested by Rothman, to be undertaken by some general fan organization. The idea was to go thru all fantasy stories and, when some approximate date in the future can be fixed for an incident, make a file card on it; eventually these would be arranged by year and the result published. A start on the job was made by Elmer Perdue, who limited himself to cases in which actual dates were given in the story. The idea comes from
(2) the history of the future sketched out by Robert A Heinlein for some thousands of years to come. This (detailed on the end-papers of many of his books) was one of the first cases of an author actually constructing and explaining a background for an entire cycle of "prophetic" stories, tho of course many authors have developed consistent segments of the future in various series. Poul Anderson later forecast a future history of his own, differing in many particulars from Heinlein's. Both caught the fannish imagination for obvious reasons.