Pinkas haKehillot or Pinkas Ha-kehilot, (Hebrew: פנקס הקהילות; notebook of the [Jewish] communities; plural: Pinkasei haKehillot) Encyclopedia of Jewish Communities from Their Foundation till after the Holocaust, is the name of each volume of a series presenting collected historical information and demographic data on Eastern European countries' Jewish communities, most of which were depopulated and whose populations were exterminated in the Holocaust. Pinkasei haKehillot is one of the most important projects undertaken by Yad Vashem in Jerusalem, concisely documenting this aspect of the history of the Holocaust.