<p>Have any of you guys ever sat in a course? This sounds like a great way to attend the lecture of a world renowned professor's class which you couldn't catch, or explore outside interests. What's the general procedure for this?</p>
<p>Columbia has no audit procedure. Generally if there are seats and it’s a medium-large class nobody will care. If you want to do it on the up and up you should talk to the professor in office hours and explain your motivation. They may or may not be ok with it.</p>
<p>However I only know a few people who’ve done it. Everyone has so many commitments it doesn’t always seem worthwhile to add another class.</p>