I just bought "Who paid the Pipers of Western Marxism" after I came into contact with a Gegenstandpunkt person and discovered what Western Marxism is. Currently I'm also finishing reading Rosa Luxemburg's Reform or Revolution and likely will read Lenin's book of the same topic later. I'm also kinda struggling with applying Historical and Dialectical Materialism on things on my own. I don't quite seem to be able to fully understand it sadly, but I'm trying.