The field of high-power laser-plasma interaction has grown in the last few decades, with applications ranging from laser-driven fusion and laser acceleration of charged particles to laser ablation of materials. This comprehensive text covers fundamental concepts including electromagnetics and electrostatic waves, parameter instabilities, laser driven fusion, charged particle acceleration and gamma rays. Two important techniques of laser proton interactions including target normal sheath acceleration (TNSA) and radiation pressure acceleration (RPA) are discussed in detail, along with their applications in the field of medicine. An analytical framework is developed for laser beat-wave and wakefield excitation of plasma waves and subsequent acceleration of electrons. The book covers parametric oscillator model and studies the coupling of laser light with collective modes.