Margohebald asks: <<<Question: Although my grandfather came from Krakow (now Poland), he was always listed as "Austrian" in census, and other documents. Would I be eligible for "Austrian" citizenship? His sister, her husband and son disappeared, from Krakow, during the Holocaust.>>>
If your grandfather emigrated when Krakow was still part of Austria (i.e. Galicia), then he left before the First World War, before Poland regained sovereignty over that area, and long before the Nazis rose to power and invaded Poland to set off the Second World War. Despite what may have been written on a foreign census, Krakow was part of Poland for two decades before World War II. So the answer to your question would be no.
If anything, you might be eligible for Polish citizenship. But you'd need to check if you meet the criteria. In general, these laws to restore citizenship in various European countries are aimed at people (or their descendants) who lost it because of Nazi or post-war Communist persecution, not those who left before the Nazi era.
All the best,
Miriam Bulwar David-Hay,
Professional journalist, editor, proofreader and translator.
Certified guide at Yad Vashem Holocaust Museum and Memorial.