This series, founded in 1990 following an earlier suggestion by Mazzino Montinari, publishes source material on Nietzsche's life, his environment, and the effects of his work. Thus, the Supplementa complement the critical editions of Nietzsche's works (KGW) and letters (KGB).

"In his impressive and painstakingly researched book, the Swiss historian David Marc Hoffmann has made an important contribution to the continuing task of uncovering evidence of editorial malfeasance and correcting the historical records surroundings Nietzsche's literary legacy."Wyne Klein in: New Nietzsche Studies 3-4/1998