This is an exercise in classic Sovietology. Fellow Sovietologists should welcome it as a contribution to their art, and some may see it as a challenge, for it takes issue with many views to which the author gives the label of conventional wisdom. Mitchell traces in detail how successive leaders of "mature" (post-Stalin) socialism gained and consolidated power, combined new policies with key appointments and organizational changes, then reached limits and a status of drift, setting the stage for new leadership. The system itself does not change. A central question for today is whether the Gorbachev regime fits the pattern or will the systemic crisis disrupt the cycle. Mitchell maintains that Gorbachev, with his "non-revolution" from above, has in fact consolidated power according to the historic pattern and that the basic elements of the system are intact.