Complex sentence: As a student, he had attempted to develop a card index listing all Jews in Germany and his articles outlined Nazi public thinking on what to do about the Jews at the beginning of the Third Reich, which includes expelling them all from Germany.
Split into simpler sentences: As a student, he had attempted to develop a card index listing all Jews in Germany. His articles outlined Nazi public thinking on what to do about the Jews at the beginning of the Third Reich, which includes expelling them all from Germany.