This edition of Arthur Radebaugh’s Closer Than We Think on mega-regions of 1975 was published in 1961 – the same year Jean Gottman published his classic, Megalopolis. The text reads:

Tomorrow’s map will be vastly different from today’s. Great patches over much of
it will indicate the super-metropolis cities which are already evolving
out of our once-separated urban centers.

The “regional cities” of tomorrow will be nearly continuous complexes of homes, business
centers, factories, shops and service places. Some will be strip or rim
cities; some will be star-shaped or finger-shaped; others will be in
concentric arcs or parallels; still others will be “satellite towns”
around a nucleus core. They will be saved from traffic self-suffocation
by high-speed transportation – perhaps monorails that provide luxurious
nonstop service between the inner centers of the supercities, as well
as links between the super-metropolises themselves.

Via Paleo-Future, pointer from Chris Briem.