Dream Machines is a history of imaginary machines and the ways in which machines come to be imagined. It considers seven different kinds of speculative, projected or impossible machine: machines for teleportation, dream-production, sexual pleasure and medical treatment and cure, along with 'influencing machines', invisibility machines and perpetual motion machines. The process of imagining ideal or impossible forms of machinery tends backwards or inwards, allowing a way for imagination itelf to be conceived as a kind of machinery, or ingenious engineering. Machines suggest to us ways of imagining the machinery we take ourselves to be, the workings not only of immune systems and neural networks, but also of dreams, desires and aspirations. This reflexivity means that representations of machines are always suffused with intense feeling. The larger aim of Dream Machines is to isolate a strain of the visionary that may be involved in all thinking and writing about machines. An imaginary machine may also be a way of imagining other kinds of thing that a machine can do and be. This is the sense in which all machines may in fact be said to be forms of media; for we have always dreamed of and with machines, always therefore dreaming through the machines we have been dreaming about.