1. Introduction.- 2. Fundamentals of Cold Plasma Electrodynamics.- 3. Relativistically Intense Electromagnetic Waves in Plasmas.- 4. Instabilities of Circularly Polarized Plane Electromagnetic Waves in Plasmas.- 5. Instabilities of Linearly Polarized Plane Electromagnetic Waves in Plasmas.- 6. Models of Nonlinear Propagation of Relativistically Intense Ultrashort Laser Pulses in Plasmas.- 7. Intense Laser Pulse Solitons in Plasmas.- 8. Relativistic and Charge-Displacement Self-Channeling of Intense Ultrashort Laser Pulses in Plasmas.- 9. Dynamics of Relativistic and Charge-Displacement Self-Channeling in Time and 2D Space.- 10. Propagation of Laser Radiation in Multiple-Stage Ionized Matter.- 11. Experiments on Laser—Matter Interaction in the Relativistic Regime.- References.