Ilya Tsvankin is a professor at the Colorado School of Mines and the director of the Center for Wave Phenomena—a research consortium. Vladimir Grechka is a senior research geophysicist with Shell, based at Houston. Through their exceptional analytical skills and keen scientific insight, both have made fundamental contributions to the study of seismic anisotropy, as well as a wide range of practical problems in geophysics. This pioneering work has been formally recognized by SEG. Tsvankin received the Virgil Kauffman Gold Medal in 1996, and Grechka received the J. Clarence Karcher Award in 1997.