Four ground level enhancements (GLE) have occurred during the ascending phase of solar cycle 21. The first two, on September 19 and 24, 1977, emanated from the same active region belonging to the old cycle more than a year after sunspot minimum. Evaluation of data recorded during the November 22, 1977, GLE reveals that the attenuation length for particles detected by an atmospheric neutron detector is 88 gm/cm2, compared with 100 gm/cm2 for the standard lead-polyethylene pile. The increased response to relativistic solar cosmic rays is displayed in all four events. The May 7, 1978, GLE was highly anisotropic over an extended period. Observations to date show that small GLEs (<25%) are equally likely to occur during Forbush decreases or quiet periods, whereas larger GLEs are concurrent with a preexisting cosmic ray storm. As in the case of other manifestations of solar activity, there is a marked north-south asymmetry in the heliolatitude of GLE-producing flares.