The Holocaust:

You can find a fairly comprehensive list in the recommended reading section of the wiki. Personally, I would select the following:

• The Holocaust: A New History (Penguin, 2017) by Laurence Rees. Up-to-date, readable.

• Final Solution: The Fate of the Jews 1933-1949 (Picador, 2017) by David Cesarani. Cesarani was dying while this book was being written so it was his ultimate work.

• The Third Reich Trilogy (Penguin, 2003-2008) by Richard J Evans. Evans has his reputation for a reason; it's a very readable and authoritative look at the Nazi period.

• The Historiography of the Holocaust (Routledge, 2004) by Dan Stone. A more academic examination of the historiography.

• Rethinking the Holocaust (Yale, 2002) by Yehuda Bauer. To understand the Holocaust, you have to understand the debates and historiography behind it.

Holocaust Denial:

• Denying History: Who Says the Holocaust Never Happened and Why Do They Say It? (UCP, 2002) by Michael Shermer, Alex Grobman and Arthur Hertzberg is probably one of the best and most recommended look at the claims of Holocaust deniers.

• Denying the Holocaust: The Growing Assault on Truth and Memory (Penguin, 1993) by Deborah Lipstadt is the most well known publication on Holocaust denial, but it's more about the movement.

• Lying About Hitler: History, Holocaust Holocaust And The David Irving Trial (Basic, 2001) by Richard J. Evans - Evans is an expert on the Third Reich and well worth paying attention to.

• Holocaust Controversies - it's a bit antiquated-looking but is one of the best websites on Holocaust denial out there. Constantly growing and adding more articles, and is run by genuine historians (at least some, I'm not sure about all of them). Personally, I don't always approve of the tone they take, but they are a fantastic resource.

• Holocaust Denial on Trial - this mainly concerns the Irving Trial and contains a huge amount of data on it. Worth reading if just to see the shocking lies he told.