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A short overview of basic problems connected with high power laser radiation interaction with solids is presented. Physical phenomena occurring during absorption of laser beam energy in solid, basic fields of application of lasers, and mathematical model of the conversion of light energy into heat are described. There are also many examples of numerically calculated temperature fields in solids caused by the interaction of laser radiation of different parameters (different power densities and interaction times), which are the results of investigation of the laser interaction with solids. These investigations have been conducted in the Institute of Heat Engineering for several years. Nomenclature a- thermal diffusivity cp- specific heat cm- latent heat (heat of melting) I- intensity of absorbed radiation q — heat flux Q- power density of laser radiation R- reflectivity Τ- temperature t- time x,y,z- spatial coordinates a — surface heat transfer coefficient ß- absorption coefficient δ- thickness of slab ε- emissivity λ- thermal conductivity Ρ- mass density σ- Stefan-Boltzmann constant τ- time of interaction- relaxation time UNTKUDUCJLIUN The study of laser interaction with solids, including laser produced plasmas, is one of the fastest growing fields of present-day physics. It has brought numer-ous innovations in material treatment, such as quality changes, welding, cut-ting, drilling, and related to high-power beam weapons. The very important and exciting field of application of high power laser beams is the safe produc-tion of clean nuclear fusion energy. Especially in the last decade, several research projects, costing hundreds million dollars, have been established in the main research centres in the world. The main goal of these projects is to develop high power lasers and investigate phenomena of laser radiation interaction with materials. In th