The dissertation of On Communism: In Defense of the New Course was written by Nagy originally in Hungarian in his forced "retirement" in 1955-56. He meant as a reply to public accusations, and explanation, justification of his New Course for fellow communists, his colleagues in the party and the bosses in the Kremlin to some extent too. This copy I found was published first in the UK in 1957, and this was printed in the US, but they state it was also distributed on the Hungary in Hungarian clandestinely.
I think I'll just present the table of contents here in picrels, to show the topics he wrote about. There are a couple that might worth a read, I'm specifically interested in the foreign relations, indebtedness to foreign countries, and the nationalism chapters. We'll see.