Systems development has moved from treating systems as purely technical problems, towards seeing systems as parts of the users' environment. Stakeholders such as operators are increasingly involved in requirements engineering in particular. Requirements engineering is balanced between cooperating with the stakeholders who own the requirements, and the need for a controlled process of development. The dilemma is that control and predefined methods tend to exclude co-operation. The article assesses progress towards the possibly unreachable goal of fully co-operative requirements engineering. Some leading methods are compared. The potential for co-operative inquiry to resolve the dilemma of co-operating manageably is discussed.