Coherent quantum optics and technology can be defined as the investigation of the principles of and methods for generating a very smooth lightwave with low fluctuations, controlling and manipulating atoms and photons and their application systems. Generation of nonclassical photons by this lightwave is also part of this area. Chapter 1 provides the reader with the definition of the coherent state of light. Chapter 2 is devoted to the principle of laser oscillation described by using the density matrix method. Chapter 3 reviews the structures and performances of representative lasers, that is gas, dye, solid-state, and semiconductor lasers. Chapter 4 defines the measures of representing the magnitude of noises and the specific noises in lasers. Chapter 5 treats the general ideas and methods of the principle of reducing the frequency fluctuations of lasers and their experimental results. Chapter 7 demonstrates several advanced lightwave application systems for communications, sensing, spectroscopy, atomic clock, quantum optics, atomic physics and test of the theory of relativity. For future progress of this field of research, Chapter 8 introduces several novel ideas for expanding the laser oscilation wavelength range, the generation of nonclassical photons, the manipulation of atoms and photons, and photonic energy storage. Chapters 1-5 form a tutorial textbook for undergraduate students, graduate students, and junior engineers. Chapters 6-8 introduce the topics which are still progressing rapidly.