In another question about the Holocaust, there is a copypasta about Holocaust questions. The second paragraph of the section on holocaust denial says this. My questions are: what are the current open questions about the holocaust and what would books in 1950 or so have said? Was holocaust denial a position any serious and respected historian/scholar would have taken so close to the event?

It is absolutely true that were you to read a book written in 1950 or so, you would find information which any decent scholar today might reject, and that is the result of good revisionism. But these changes, which even can be quite large, such as the reassessment of deaths at Auschwitz from ~4 million to ~1 million, are done within the bounds of respected, academic study, and reflect decades of work that builds upon the work of previous scholars, and certainly does not willfully disregard documented evidence and recollections. There are still plenty of questions within Holocaust Studies that are debated by scholars, and there may still be more out there for us to discover, and revise, but when it comes to the basic facts, there is simply no valid argument against them.