Laser induced plasmas are of significant interest in a large domain of research and industrial applications including ablation, micro-machining, photochemistry, fission, fusion, materials characterization, aerospace, combustion and space applications. This book covers the fundamentals of laser induced gas breakdown for infrared and ultraviolet laser radiation. The basic principles and theories of laser induced plasma formation by multi-photon ionization and cascade ionization process are discussed in detail. The laser breakdown thresholds that are extended to microwave frequencies through quantum correction and universal scaling processes are conferred elaborately. Laser shadowgraphy diagnostics to study the spatio-temporal shock wave propagation and hydrodynamic behavior as well as to measure plasma electron temperature; Two-wavelength laser interferometry to measure spatio-temporal plasma density and optical emission spectroscopy diagnostics to measure plasma rotational and vibrational temperatures of the laser induced plasmas are elaborately covered. The modeling of plasma decay through diffusion, attachment, 2-body and 3-body recombination processes is demonstrated.