Multiple reflections have been a major problem since the beginning of seismic exploration. In the last five decades a range of methods have been developed to suppress these refl ections and enhance the primaries. This book provides an overview of these techniques, starting with the deconvolution-based methods from the 1960s, via the move-out discrimination techniques of the 1980s and ending up with wave-equation based methods from the 1990s and their 3D extensions as developed in the 2000s. Furthermore, the current challenges in multiple removal and their relation with seismic imaging and inversion are treated. Besides this overview, the book also discusses processing concepts that are required to better understand various technologies, such as high-resolution seismic data transforms (Fourier, Radon), adaptive fi ltering techniques, wave-equation based forward and inverse wave propagation and the processing of seismic data in different transform domains. The emphasis is not to thoroughly treat the mathematics but to present some understanding of the physical concepts behind each method, illustrated with clear examples.