Are there any of these about the Wehrmacht soldiers? All I'm ever able to find are books about the higher ranking officers or the political officials, and that's not what I've been looking for. To put this into context, I'm writing a sort of story and I would like to read more about the personal lives of the Wehrmacht soldiers to better understand them.
A problem with German autobiographies is they tend to be proactive in denying their involvement in the crimes of National Socialism. Rudel's autobiography Stuka Pilot pretty much defends the rationale behind Germany's invasion of the Soviet Union. Therefore, one should be judicious and discriminating when looking for first-person accounts.
One of the more interesting books on a Wehrmacht officer is Reluctant Accomplice: A Wehrmacht Soldier's Letters from the Eastern Front which is translated and edited by his son, Konrag Jarausch, a very notable historian of modern Germany. Another posthumous account that does not suffer from postwar editorializing is Willy Peter Reese's A Stranger to Myself: The Inhumanity of War, Russia 1941-44.
For secondary sources, Omer Bartov has done a lot of work on the social makeup of the German army. In particular, his books Hitler's Army: Soldiers, Nazis, and War in the Third Reich and The Eastern Front, 1941-45: German Troops and the Barbarisation of Warfare are adept at parsing out details like NSDAP membership within the ranks.