The fourth volume of the series Sylloge Nummorum Sasanidarum, Paris-Berlin-Wien, covers the period of Khusro I (531–579). His long reign is generally considered the high point of Sasanian history. For the first time, a detailed numismatic analysis based on a representative collection of material can be presented. One focus is on the mint abbreviations, because analysis of these gives access to important new information for Sasanian administrative and regional history. The value of Sasanian coinage for the reconstruction of political history is also evaluated. One chapter is dedicated to material analysis. The catalogue covers about 880 coins from the collections in Paris, Berlin, and Vienna, as well as about 1200 additional coins. This is the most substantial documentation of the coinage of Khusro I compiled so far.