The document discusses two models of organizational change: the punctuated equilibrium model and shapes of organizational change. The punctuated equilibrium model describes periods of rapid change sandwiched between long periods of incremental change and adaptation. It also discusses four types of organizational change. The second part examines two issues - shapes of organizational change (radical vs incremental) and the role of top vs middle management in change. The case study of Heineken shows examples of both radical and incremental change driven by top or middle management in response to environmental shifts.