James Glazov’s book is excellent. However, it might be supplemented by a history of the “Left.” which derives its name from the French Revolution – the National Assembly was seated in a semicircle, with Jacobins led by Maximillian Robespierre on the far left and the monarchists and clericals on the far right. Revolution became fashionable in the 19th century, with revolutionaries thinking of themselves in the tradition of the Jacobins and so “Left.” Vladimir Lenin regarded himself as such, establishing the Soviet Union in a permanent “Reign of Terror” in order to prevent “Thermidor” (the month in which Robespierre and his colleages were overthrown and executed).
Robespierre gave a speech at the National Assembly in February of 1794, justifying the use of terror to establish virtue, hence the origin of the term “terrorism.” Sergei Nechayev in 19th century Russia invented ways of bringing the revolution (like Saul Alinsky) – see his Catechism of the Revolutionary.
The enthusiasts for mass slaughter and the like called “the Left” which James Glazov describes,are followers of Robespierre.
