The nature and importance of the Nachlass from Kierkegaard's hand is not well known, especially to researchers outside Denmark. At his death, Kierkegaard left behind an enormous amount of unpublished material in various folders, journals, and notebooks, and on loose pieces of paper. This material includes observations and analyses on various topics, sketches and outlines for possible works, reading and lecture notes, as well as autobiographical reflections. This Element is an attempt to make this rich and interesting material better known to international Kierkegaard readers. It shows how Kierkegaard's posthumous writings are interesting and valuable on their own and serve to illuminate his well-known published works.