The term machine is used here to embrace active systems with moving parts, where controls may take full advantage of electronic technology, but may still vary from automatic to manual. Inevitably, some of the issues around ‘machine control’ have already come up, for example, in relation to intervention by users. Indeed, there is a distinct mirroring of aspects covered in Chapter 4. Here however, as with the previous chapter, the emphasis is directed more strongly towards the intentions of the designers, and in particular where the performance of the system appears to be subject to dilemmas, limitations or shortcomings. This slant, with technology sometimes in the dock together with dubious decisions made by professionals, has again been subdivided into three main topics: movable controls attached to glazing, solar air collectors, and issues associated with interactive control and management.