This book provides a comprehensive overview of bosonization, a powerful nonperturbative technique for studying many-body systems. The first part delves into the technical aspects of bosonization, covering topics such as one-dimensional fermions, the Gaussian model, Hilbert space in conformal theories, Bose-Einstein condensation, non-Abelian bosonization, and models like the Ising and WZNW models. The second part explores applications of bosonization to realistic models, including the Tomonaga-Luttinger liquid, spin liquids in one dimension, and the spin-1/2 Heisenberg chain with alternative exchange. The third part addresses quantum impurities, discussing potential scattering, the X-ray edge problem, impurities in Tomonaga-Luttinger liquids, and the multi-channel Kondo problem. The book is designed to serve as a valuable reference for researchers and graduate students in theoretical physics, condensed matter physics, and field theory, highlighting the parallels and connections between high energy physics and condensed matter physics, particularly in the context of strongly correlated low-dimensional systems.This book provides a comprehensive overview of bosonization, a powerful nonperturbative technique for studying many-body systems. The first part delves into the technical aspects of bosonization, covering topics such as one-dimensional fermions, the Gaussian model, Hilbert space in conformal theories, Bose-Einstein condensation, non-Abelian bosonization, and models like the Ising and WZNW models. The second part explores applications of bosonization to realistic models, including the Tomonaga-Luttinger liquid, spin liquids in one dimension, and the spin-1/2 Heisenberg chain with alternative exchange. The third part addresses quantum impurities, discussing potential scattering, the X-ray edge problem, impurities in Tomonaga-Luttinger liquids, and the multi-channel Kondo problem. The book is designed to serve as a valuable reference for researchers and graduate students in theoretical physics, condensed matter physics, and field theory, highlighting the parallels and connections between high energy physics and condensed matter physics, particularly in the context of strongly correlated low-dimensional systems.