An English translation of the paper of Max Planck (1943) about “Zur Geschichte der Au ndung des physikalischen Wirkungsquantums: or: :The history of the discovery of the physical quantum of action” to provide a readable version of the German content.

Abstract

Since the appearance of the elementary quantum of action marks the beginning of a new epoch in physical science, I feel the need and the obligation towards the physicists of a later generation to describe in a summarising presentation, to the best of my knowledge, the repeatedly tortuous path by which I arrived at the calculation of this universal constant, as it is reected in my memory.