How did the Nazis determine if Someone is Jewish?

As I read the posts from this morning, I see that the answer to the question of how the Nazis determined if someone was Jewish still eludes those who have tried to figure out the answer. It is a difficult question, but rather than having everyone continue to wrestle with the question, I am linking you to a source that accurately describes German law during the time of the Third Reich. Use this article to guide your group discussions.
The Concept "Jew" in Nazi German "Race" Legislation