Ok, so for context: I read about this yesterday and at first, I was really really confused because the news source I perused didn't include the dates of the duty diary (Dienstkalender in German, meaning it is something of an official organizer with meetings, dates, and some quick notes) of Himmler that had been found. The main reason for my confusion was that the Dienstkalender of Heinrich Himmler form the years 1941/42 has been published since 1999 after Peter Witte and Michael Wildt among others found it in 1991 in the former KGB special archives in Moscow together with the diary from 1945. What has been discovered now in the archives of Podolsk are the diaries for 1938, 1943, and 1944, which had been previously not known to still exist. Now Dieter Pohl and Michael Uhl are working on an edition of these diaries, meaning that they will insert commentary and explanations in the form of footnotes, most likely.

If the published duty diaries of 1999 are an indication, these new discoveries will not completely turn our understanding of what happened on its head but will add interesting new details, maybe clearing up a few issues where historians previously had been puzzled or were not aware of the full process of decision making.

The format of these things is that it contains pages for every meeting Himmler had, including the date and with whom prepared by his adjutant and the notes Himmler made of that meeting. Again, taking the already published ones as an example, they helped immensely at establishing certain timelines historians hadn't been sure of previously. One such example is that some historians have long suspected that the order for the murder of all European Jews, especially the systematic murder of the German Jews, had been issued in December 1941. Himmler's duty diaries of that year have delivered strong evidence for this theory: On December 18, 1941 Himmler had a meeting with Hitler. In his duty diary he notes about said meeting: "Jewish Question. | Exterminate as Partisans". This taken in connection with other evidence, especially Himmler chastising the Higher SS and Police Leader of Lithuania in early December for murdering German Jews and our knowledge of what was discussed at the Wannsee Conference that was originally scheduled for December 8, 1941 points to the decision to kill all the Jews of Europe systematically at some point in early December.

Similarly, these diaries can give a certain insight when documents are missing. We know from an order by the head of Gestapo Heinrich Müller from October 2, 1942 that the order was given to deport the last remaining Jews imprisoned in Concentration Camps in Germany to camps outside of Germany. Himmler's duty diary clears it up that this was in fact Himmler's order from late September that year rather than Müller's own initiative.

So bar, any huge surprise (which I think won't happen), these duty diaries will help us establish timelines and clear up certain responsibilities, which in turn could either slightly change or also slightly deepen our understanding of how certain policies were implemented, who pushed for what policies, and what kind of thoughts by important actors preceded certain decisions. In that sense, they most likely will be rather illuminating but won't contain any new huge surprises.