In developing countries mainstream planning practitioners show little awareness of the urban land markets in which they intervene. The wide-spread ineffectiveness of land use controls may reflect a failure to understand market factors as they affect developers, politicians and the poor. Land acquisition—critical to so many government development programmes —is becoming an impossibility. The market effects of public capital investments are allowed to subvert plan strategies when they could possibly assist them. To be effective in the urban affairs of developing countries, planning must greatly reduce its ignorance and neglect of market forces.