Core-collapse supernovae (SNe) come in a variety of subtypes. The SNe II-plateau (II-P) show a long plateau in their light curves, as well as classical P Cygni Balmer line profiles in their spectra. The SNe Il-linear (II-L) show a linear decline in their light curves after maximum, and the blue absorption trough in the Balmer lines is missing, leaving only broad emission profiles. The SNe II-narrow (IIn) show a narrow profile atop a broad base to the Balmer emission. The SNe lb exhibit no hydrogen lines, but prominent He lines instead. The SNe Ic also show no H, but also weak or no He, with their spectra dominated by intermediate-mass elements. The SNe lib start out appearing as SNe II(P), but in time evolve spectrally to resemble SNe lb, with a later resumption of broad Balmer profiles, as in the case of SN 1993J (see Filippenko 1997 for a review of SN types). The progression from SNe II-P, II-L, Iln, lib, lb, through Ic may be due to the degree of stripping of the H-rich stellar envelope. Binary star systems are likely the progenitors of many core-collapse SNe. In fact, we might expect ≳40-50% of all such SNe to arise from binaries (e.g., De Donder & Vanbeveren 1998).