It has happened many times before in human history that masses of men, women and children were murdered for no other reason than their being supposedly of an inferior race or creed.

What is special about the Holocaust are especially the very large number of victims it produced in a short time (some three years: 1941-1944); the bureaucratic and systematically planned way of murdering; the method of murdering, in concentration camps, with gas; and the fact that it is rather well documented and researched.

One gathering of evidence of it is Laqueur Ed.'s "The Holocaust Encyclopedia".