The entire course of antenna development appears to have been altered by the rapid evolution of the self-phasing principle. Salient characteristics of adaptive, or self-phasing, antennas are described by means of a semiquantitative approach Antenna research is considered by some shortsighted individuals to be a “dead field.” The statement has been repeated many times since the end of World War II, but fortunately for those who make a living in this field, the body shows a great reluctance to lie down for the burial. While a quick perusal of the popular antenna publications indicates a great deal of “rediscovery” in progress, the relatively small number of researchers responsible for most of the progress are still pushing back the frontiers. Recent antenna developments, in fact, occasionally have bordered on the glamorous.