Josh, as we called him, was my favorite teacher of the year. Unfortunately, he's leaving Columbia forever, so this is the last review anyone will write of him.
His class consisted of great, enlightening mini-lectures followed by discussion. He guided us towards interesting questions and helped us get the most out of the readings, including when we clearly hadn't read - he would take us very gently through the main ideas. The only exception to this was after his wife had a child, at which point he clearly started putting less time into his notes.
Made an effort to challenge our views, but never to be an ass about it.