Harmonic Function is a mathematical textbook written by William Elwood Byerly and first published in 1896. The book provides a comprehensive introduction to the theory of harmonic functions, which are mathematical functions that satisfy Laplace's equation. Byerly covers topics such as the properties of harmonic functions, their applications in physics and engineering, and the mathematical tools used to study them, such as complex analysis and potential theory. The book is written in a clear and concise style, making it accessible to both students and researchers in the field of mathematics. Harmonic Function is considered a classic in the field of mathematical analysis and is still widely used and referenced today.This scarce antiquarian book is a facsimile reprint of the old original and may contain some imperfections such as library marks and notations. Because we believe this work is culturally important, we have made it available as part of our commitment for protecting, preserving, and promoting the world's literature in affordable, high quality, modern editions, that are true to their original work.