The concepts of linear optics are applied to the physics of energy coupling into laser‐produced plasmas currently of interest in laser‐initiated fusion research. The effects of polarization and angle of incidence upon reflection and refraction are recalled. Singular behavior occurs in the region of the plasma where the real part of the dielectric constant vanishes, the so‐called ’’critical density’’ region. The effective generation of Langmuir waves at the surfaces of bounded plasmas through the optical resonance of obliquely incident electromagnetic radiation is heuristically discussed. Enhanced electric fields, enhanced ’’collisionless’’ damping, harmonic generation, the presence of energetic electrons, and density profile modifications which result near the critical density from the excitation of these plasma waves are described. While more complex plasma processes may occur, they are not within the scope of this review.