This book extensively discusses the prominent scientific applications of topography and astronomy. It presents latest information about the experimental and theoretical aspects of some interferometry methodologies. It also discusses their applications in astronomy and topography. It presents valuable information on interferometry techniques used for precise measurement of surface topography in engineering applications and interferometry applications related to Earth's topography. It also discusses applications of interferometry in astronomy with special emphasis on techniques for detection of planets outside our solar system. The topics offer an opportunity to readers to gain insights about interferometry techniques and encourage researchers in developing new interferometry applications.