Thought you knew what primary and multiple meant? Find new, useful definitions that accommodate a complex multidimensional earth in Multiple Attenuation (SEG Geophysics Reprint Series No. 23). This book covers 55 years of fascinating scientific discovery - from the time when geophysicists argued over whether it was even possible to see multiple reflections in seismic data to the very latest developments in data-driven multiple-attenuation methods. Seve al challenges have renewed interest in multiple attenuation. These result from (1) the industry trend to deep water, (2) complex multidimensional heterogeneous media, (3) ocean-bottom acquisition, and (4) 3D data requirements on towed-streamer data. To meet these challenges, new data-acquisition and multiple-removal technologies are on the horizon. This book provides the background to help geoscientists make the most of these coming developments. The opening chapter presents papers of historical interest, and the volume concludes with a speculative chapter about multiples used as signal. In between are seven chapters that cover unique aspects of multiple-attenuation technology, including deconvolution, moveout discrimination, data-driven prediction, practical issues, and tutorials and case histories. The volume includes a new tutorial that introduces and contrasts the two main approaches to data-driven multiple prediction. All geoscientists who work with seismic-reflection data will find this volume useful. Seismic survey designers will learn how field parameters affect various multiple-attenuation methods. Seismic data processors will find discussions of the advantages, disadvantages, and limitations of different algorithms. The volume will help seismic data interpreters to understand multiple attenuation so they can better judge whether that puzzling event is a primary or a residual multiple. The book is also an indispensable reference source for researchers, students, and geophysical software developers.