In April of 1968 I gave a series of lectures on the structure, evolution, and stellar content of nearby galaxies at the University of California in Berkeley. An outline of these talks was printed as a slender volume entitled “The Galaxies of the Local Group” (van den Bergh 1968a). Since the publication of this booklet the number of known members of the Local Group has doubled. Furthermore both the quantity, and the quality, of the data that are available on the previously known Local Group members have increased enormously.

Particularly exciting developments since 1968 have been (1) the discovery of the Sagittarius dwarf, which is the nearest external galaxy, (2) the discovery of six dwarf spheroidal companions to the Andromeda nebula, (3) the application of CCD detectors to studies of stellar populations in various Local Group systems, and (4) deep high-resolution observations of various objects in the Local Group with the Hubble Space Telescope. With the presently available enlarged sample, and the improved quality of data on individual objects, we are now in a much better position to start exploring the evolutionary history of the Local Group and its constituent galaxies. Finally (5) it has become clear during the past quarter century that the masses of dark matter halos are typically an order of magnitude greater than the masses of the baryonic galaxies that are embedded within them.