I turned to Ron Unz's article "American Pravda: Holocaust Denial." Just as incompetent Wikipedia attributed David Irving's views to me, no doubt Wikipedia will credit me with authorship of Ron Unz's article.
Ron Unz is a prolific reader who provides reliable accounts. His article reports on books that promote the official Holocaust story and on books that have researched the Holocaust and find facts different from the official story. The best way to get your feet wet on any subject is to see what Ron Unz has to say. Unz, of course, is thorough, because he understands the importance of truth. Reading his articles is like reading a monograph. This one is 18,000 words. It takes committment. You have to really want to know. The alternative is to read the dozen plus books that Unz reports on. So, it is either Unz's 18,000 words or a couple of million words. I suggest the shortcut that Unz provides. If it spurs your interest, you can start on the books.
Unz's article begins with a map of Europe showing 15 countries in which any denial of the official Holocaust account, whether true or not, lands the denier in prison.