With the fascist danger rising in Germany, and the imperialist powers of the United States and Great Britain looming not far behind, in the late 1930’s a new danger would present itself in the young Soviet Union; one which would forever scar the landscape of Communist politics — Trotskyism. Published in 1937, in the midst of the trials in Moscow, Mastering Bolshevism by General Secretary J. V. Stalin is a masterful deconstruction of the Trotskyite error, what it is, how it came to be, and how it threatens the work of Socialist construction.