It is fairly well known the Gra thought that a well known group of Orthodox Jews was the Sitra Achra. [Or had fallen into the "Dark Side" in English vernacular and were teaching doctrines that were subverting the Torah, all while pretending to be committed Orthodox Jews. [This group using good and experienced operators, was able by the use of psychological methods, to alter the loyalties of an individual so deftly that he himself did not suspect that he has changed.] What is the great news? We know this. It is uncomfortable to know this for people that find inspiration in the teachings of Breslov but that is no reason to subvert the simple historical facts . In fact, there is an idea of Nachman that helps me to deal with the fact that there are disagreements between tzadikim (saints). He considers arguments between saints to be an essential part of the natural order,-without which there could not be free will. [Ontological undecidablity see Kelley Ross and Schelling ]
When I asked someone from Bnei Brak to bring me this three volume set, I was told it was written by a "baal teshuva" (newly religious). The ultimate put-down. However, the book was by a well known grandson of a famous Rav in Bnei Brak and he was asked to write the book by Rav Kanievsky and research for five years was done to produce it.] At any rate, my learning partner suggested that it is important to find this book because apparently it has a good analysis of how the Gra thought people should learn Torah.