This triennial report (1996-1999) reviews the subject from a somewhat personal angle, mostly related to binary star formation and young binary star populations – a subject whose time had come in the early 1990s and is now in full swing.

Many astronomers have searched for binary systems among main-sequence stars, and two large-scale surveys published in 1991 and 1992 have already become classics. Well before they became famous for finding extrasolar planets (see below), observing teams led by Michel Mayor (Geneva Observatory) and Geoffrey Marcy (San Francisco State Univ., now Univ. of Calif, at Berkeley) spent many years searching for low-mass stellar companions of nearby stars. The late Antoine Duquennoy and Mayor surveyed all solar-type dwarfs (spectral types F7 through G9) within 20 pc of the Sun, while Debra Fischer and Marcy studied stars with somewhat lower mass (M dwarfs) slightly nearer to the Sun.