In 1900 Max Planck introduced a quantum constant into his mathematical expression for the energy distribution of blackbody radiation. This book is a revolution in 20th century physics. The first fifty pages examine heat radiation from the perspective of classical optics, including topics like radiation at thermodynamic equilibrium, Kirchhoff's law, and blackbody radiation. The next fifty pages, deductions from electrodynamics and thermodynamics, were substantially more mathematical. Planck discussed the Stefan-Boltzmann law of radiation and the Wien displacement law in detail as well as spectral distribution of energy radiation. Section III presents a general procedure for calculating entropy and introduces his quantum hypothesis. This book is a great help for students studying physics, for teachers and for anyone interested in this science.