Quantum measurement theory and its applications Recent experimental advances in the control of quantum superconducting circuits nano mechanical resonators and photonic crystals has meant that quantum measurement theory is now an indispensable part of the modelling and design of experimental technologies. This book aimed at graduate students and researchers in physics gives a thorough introduction to the basic theory of quantum measurement and many of its important modern applications. Measurement and control is explicitly treated in superconducting circuits and optical and opto mechanical systems and methods for deriving the Hamiltonians of superconducting circuits are introduced in detail. Further applications covered include feedback control metrology open systems and thermal environments Maxwells demon and the quantum to classical transition