Abstract: In this article, theories of several types of surface waves and guided waves developed in recent years in seismology are reviewed. These include the small scaled surface waves in the sedimentary strata, the larger scaled crustal Rayleigh and Love waves and the world circling Mantle Rayleigh waves and G-waves. Different kinds of channel waves occurring in Gutenberg's low-velocity channels are also described. The use of dispersion curves of surface waves in the interpretation of the earth's crustal structure is discussed with particular emphasis on the uniqueness of the solution.