  This article presents recent progress in the theory of quantum measurement
engines and discusses the implications of them for quantum interpretations and
philosophical implications of the theory. Several new measurement engine
designs are introduced and analyzed: We discuss a feedback based
atom-and-piston engine that sharply associates all work with successful events
and all quantum heat with the failed events, as well as an unconditional but
coherent qubit engine that can attain perfect efficiency. Any quantum
measurement of an observable that does not commute with the Hamiltonian will
necessarily change the energy of the system. We discuss different ways to
extract that energy, the efficiency and work production of that process.
