I am fascinated by the Historians debate regarding the Holocaust. I find the question of intentionalism or functionalism fascinating in general, but particularly noteworthy in the implementation of the Final Solution.

Essentially- Intentionalism- The Holocaust was planned and instituted by Hitler and the Nazi Party from above. Functionalism- The Holocaust came about from lower levels as an answer to problems and issues arising at those levels.

EDIT Please note that this is not asking for debates between people in history. It is asking about debates among historians about the interpretation of historical events.

Reading List on the topic:

General Explanation of the Debate- http://eview.anu.edu.au/burgmann/issue2/pdf/ch06.pdf

Intentionalist Historians & his/her work-

Lucy Dawidowicz- The War Against the Jews, 1933-1945

Gerald Fleming- Hitler and the Final Solution

Functionalist Historians & his work-

Hans Mommsen- From Weimar to Auschwitz

Christopher Browning- The Origins of the Final Solution