This chapter provides an overview of the content and structure of the book "Foundations of Potential Theory" by Oliver Dimon Kellogg. The book, originally published in 1929 and reprinted in 1967, systematically treats potential functions, aiming to serve as both an introduction for students with a background in calculus and a reference for mathematicians. It emphasizes the use of physical intuition and rigorous proofs to ensure clarity and depth. Key topics include the force of gravity, fields of force, the potential, the divergence theorem, properties of Newtonian potentials, harmonic functions, electric images, Green's function, sequences of harmonic functions, fundamental existence theorems, and the logarithmic potential. The chapter also highlights the importance of exercises for mastering the subject and acknowledges the contributions of various individuals who supported the author's work.This chapter provides an overview of the content and structure of the book "Foundations of Potential Theory" by Oliver Dimon Kellogg. The book, originally published in 1929 and reprinted in 1967, systematically treats potential functions, aiming to serve as both an introduction for students with a background in calculus and a reference for mathematicians. It emphasizes the use of physical intuition and rigorous proofs to ensure clarity and depth. Key topics include the force of gravity, fields of force, the potential, the divergence theorem, properties of Newtonian potentials, harmonic functions, electric images, Green's function, sequences of harmonic functions, fundamental existence theorems, and the logarithmic potential. The chapter also highlights the importance of exercises for mastering the subject and acknowledges the contributions of various individuals who supported the author's work.