'Quantum Engineering' covers the theory, design, fabrication and applications of quantum coherent solid-state structures. This updated and expanded second edition provides a self-contained presentation of the theoretical methods and experimental results in both first and second waves of quantum technology innovation. Topics span the quantum theory of electric circuits, theoretical methods of quantum optics in application to solid-state circuits, the quantum theory of noise, decoherence and measurements, Landauer formalism for quantum transport, the physics of weak superconductivity and the physics of two-dimensional electron gas in semiconductor heterostructures. The author introduces microscopic ion- and defect-based qubits, currently among the most successful platforms for quantum computation and quantum sensing. Reflecting the significant progress of quantum hardware, state-of-the-art implementations such as quantum metamaterials and quantum reservoir computing are also added to the discussion. Written for graduate students in physics, this book also serves electronic engineers working in quantum engineering.