This volume includes new publications of Max Planck's "Scientific Autobiography," eight lectures on theoretical physics delivered at Columbia University in the Spring of 1909 and his Nobel Prize Address "The Origin and Development of the Quantum Theory." The idea of selecting Planck's works for this volume was simple - to let him talk about his research in his "Scientific Autobiography" and then the selected lectures on theoretical physics demonstrate his achievements and his views on "The Present System of Theoretical Physics" as he himself described the subject of his lectures. The volume should be of interest to experts, students and all interested in the foundations of physics. It could be particularly helpful to students of physics because they will be exposed to the way of doing physics by one of the greatest physicists of all time.