For several years the author has concerned himself with reviews and reexamination of basic concepts of psychoanalytic theory and practice. In this paper his exposition considers the process of free association and the basic rule. After referring to Hartmann's self-exclusion of the ego and to Kris's regression in the service of the ego, Bellak submits his own idea of the oscillating function of the ego: a swing from regression to vigilance of cognitive, adaptive, and synthetic functions. It is upon this oscillating function of the ego that the process of free association is specifically predicated. Following a brief discussion of free association as a process, he describes some inherent clinical problems and suggests a method of studying such disturbances by relating them to different ego functions. In view of the widened scope of psychoanalysis today, the author recommends some systematic changes in psychoanalytic technique consistent with Eissler's theory of parameters.