This book offers a simultaneous treatment of the theory and numerical application of boundary-value problems related to the determination of a precise geoid from gravimetric data. The following subjects are discussed: topographical effects and their computations in precise gravimetric geoid determination, the downward continuation of a harmonic function, Stokes' problem formulated on an ellipsoid of revolution, spherical Stokes' problem with ellipsoidal corrections involved in boundary conditions for an anomalous potential, and the altimetry-gravimetry boundary-value problem. The answer to a number of scientific problems, raised and discussed in geodetic literature over the past years, can be found here. The book is intended for scientists and advanced graduate students.