This book bridges the gap between the classic texts on potential theory and modern books on applied geophysics. Introductory chapters discuss potential theory with emphasis on those aspects particularly important to earth scientists, such as Laplace's equation, Newtonian potential, magnetic and electrostatic fields, conduction of heat, and spherical harmonic analysis. Later chapters apply these theoretical concepts specifically to the interpretation of gravity and magnetic anomalies, with emphasis on anomalies caused by crustal and lithospheric sources. The book is ideal for graduate students and researchers in applied geophysics.