"There's a book on the history of philosophy by Teodor Oizerman the title of which I forget."
Charles, I think you have in mind Theodore Oizerman's Dialectical Materialism and the History of Philosophy. Progress, 1982. A superbly lucid study studded with insights about the Hegel-Marx relation. Oizerman includes an analysis of what Marx learned from Hegel's study of the history of philosophy in developmental terms (the basic categories in any form form of development, idealist or materialist) as well as an argument for Marx's indebtedness to Hegel's theory of reason. Fine chapter as well on the social meaning of Hegel's philosophy. Throughout important elements of Marx's critique of Hegel are discussed. Meant to include Oizerman; glad that you reminded me. Again, this relationship is interpreted in many contradictory ways. Oizerman's interpretation has the added virtue of absolute clarity of purpose and prose style.
Yours, Rakesh