But at the time the Federation Ship Champion returned to Terra from Mars, the "flapper system" had been expanding for more than a century and had reached a stage of great intricacy, with many persons employed solely in carrying out its rituals.  The importance of a public personage could be estimated by the number of layers of flappers cutting him off from ready congress with the plebian mob.  They were not called "flappers," but were known as executive assistants, private secretaries, secretaries to private secretaries, press secretaries, receptionists, appointment clerks, et cetera.  In fact the titles could be anything - or (with some of the most puissant) no title at all, but they could all be identified as "flappers" by function: each one held arbitrary and concatenative veto over any attempted communication from the outside world to the Great Man who was the nominal superior of the flapper.