The heretics, Jewish people, and lepers were all minority groups who underwent hardships under different circumstances. However, R.I. Moore's main argument is that the similarities between these groups being attacked is not just a coincidence. Rather, he feels that these all occurred because of the pattern of prosecution in medieval society. He believes that the persecution was started by princes and prelates, not by the majority populations.
In the first two chapters of the book, he goes over the patterns of prosecution in these groups. He believes that those who reform end up becoming prosecuted in the next generation. For the Jews, he talked about how they were Anti-Christians, and he believes that the emperors had power over protecting them, which meant that they also had the power of exploiting Jews. For the lepers, he notices that the prosecution seemed inflated for the number of lepers that there were. He believes that this shows the anxiety that people living under this age were under, and that those in charge led the "mob" to prosecute these minority groups.