The monograph presents the generalized results of theoretical and experimental studies of the interaction of laser radiation with metals during laser cutting of sheet materials. Attention is paid to the construction of physical and mathematical models taking into account the diversity of thermophysical processes, the main of which are heating, melting and removal of gas stream products . The computational technology of modeling of spatial jet streams of working gas taking place during laser cutting of thick-sheet materials is proposed. Original results of observation and visualization of processes inside the laser cut in laboratory conditions are presented. The results of experimental studies performed on the automated laser technological complex ITPM SB RAS on laser cutting of thick sheets of stainless, low-carbon steels and titanium. For specialists in the field of laser processing of structural materials, as well as for graduate students, undergraduates and university students .