to Coherent Extreme-Ultraviolet and Soft X-Ray Sources.- Short Survey of XUV Emission Mechanisms and Sources.- XUV Optics.- Coherent XUV Radiation Beams.- State of the Art and Prospect of X-Ray Lasers.- Beginnings.- General Features of X-Ray Lasers.- Propagation of XUV Laser Beams.- Saturated XUV Lasers.- Recombination Lasers.- Schemes for Future Soft X-Ray Lasers.- High Harmonic Generation.- Survey of the Theoretical Background.- General Characteristics of High-Order Harmonic Emission.- A Survey of Coherent XUV Sources Applications.- Time-Resolution About 100 Picoseconds.- Time-Resolution About One Picosecond.- Subfemtosecond Time-Resolution.- Future Prospects.