and the primary textbook, written by the president himself. >> i wrote "the art of the deal." one of the all-time best selling books about deals and deal making. >> but how to go up against the brash billionaire. lesson one, threaten to leave before the negotiations have even begun. >> if you can't say you're going to walk, then you can't make a dea deal. >> and he's probably brushing up on that tell all white house book, "fire and fury". >> but why stop at memorizing trump's deal making tips. the north koreans are hungry for any advantage, maybe even studying the president's source of fuel. as kim jong-un prepares to sit down at the negotiating table, he also might want to practice his golf swing if talks move to the links. >> when we play golf, we talk