Actually, it was a Frenchman, Jean Gottmann, whose book "Megalopolis" was published in 1961. He originally was referring, of course, to the Eastern Seaboard, but continued metropolitan growth has led to dozens of similar situations worldwide. Gottmann said as much in "Megalopolis Revisited" in 1987.

Personally, I've never liked the extra syllable in there; for that matter, maybe neither did Gottman, since he used "megapolitan" instead of "megalopolitan" as the adjective form.

The Lincoln Institute of Land Policy offers a better definition, perhaps, than Wikipedia's:
http://www.lincolninst.edu/pubs/PubD...spx?pubid=1039

In any case, some of these regions strike me more as convenient geographic constructs than as genuine supra-metropolitan units that shape human activities. Chicago is about 400 miles from Pittsburgh, Omaha, and Kansas City; Chicago arguably has similar economic and social ties to the western cities as to Pittsburgh -- so why, besides the fact that Ohio is more populous than Iowa, draw the megapolitan boundary east from Chicago? (Maybe one useful and easily obtained measure might be intercity passenger and freight flows.)

Also, note the distinction between "megalopolis" (and its synonyms, like "conurbation," referring to multicentered regions) and "megacity" (a single metro area with over 10M residents).