I was expecting way too much from this work. I personally wouldn't recommend this as an introduction.
It absolutely butchers what Idealism is which just adds to confusion as to what "idealism" even means. Idealism, especially the more serious strands, are not the "subjective Idealism" or "religious" systems that Cornforth disparages in the first chapters; in fact, one could argue that the Idealism after Kant basically goes too far and basically negates subjectivity (be that of "God" or of individuals as they all fall into the development of the concept).
The idea of what "Metaphysics" also is woefully left unexplored as well, it has also been a source of confusion for a lot of people since the typical Marxist usage of the term isa little distinct from how other schools of philosophy use it.
At least the newer editions did some editing and self-criticism and point out that Lysenko was wrong since those statements aged poorly lol
Lots of stuff that's not particularly new or exciting. You might as well read the O.G works by Hegel, Marx, Engels, Lenin, Mao, etc.