An endearing curmudgeon, Mark will never let you get away with a lame argument. He challenges you to examine your thinking. And, as Socrates said, the unexamined life is not worth living. He'll challenge you, but he won't flake out. He's a good and patient listener. He has a wonderful laugh. He uses his formidable computer science superpowers only for good. He knows that evil corporate chain bookstores are only there provide a public library for you. He single-handedly keeps the fine restaurants of Chicago afloat. He's solid, Jack.