In plan-work as in other forms of work, the motor of change is struggle for possession of the means of production: 1. Plan-making is a form of work: the "plan-work". Planning is work, and hard work at that. The plan-work concentrates work of several different kinds, some general (eg forms of speaking, writing and meeting) and some specific to planning (eg methods of evaluation and choice). It is the planners who: perform the plan-work. 2. The work of planners is to design work for others. The plan-work intervenes in the work of others; it plans their work. Intervention is via (i) a plan, a substantial body of documentation, and (ii) learning, the subjective intellectual property of the planners. 3. The plan—work is subjected to struggles for possession of the means of planning. The "modernization" of plan-making in the 1960s represents one such conjuncture, in which both the relations and forces of plan-production were transformed in a short but profound struggle with defenders of the old order.