For the critics baffled by President Donald Trump’s Greenland gambit, there is an overlooked advantage in covering this president. Unlike most political figures, Trump has already published a user’s manual for how he negotiates; the classic Art of the Deal, written in 1987 by journalist Tony Schwartz (who, when Trump ran for office in 2016, called the book “the greatest regret of his life, no question.”). The book details Trump’s experiences negotiating his way to the top of New York’s vicious real estate market, and the tactics he learned along the way. As President, particularly in his second term, Trump has clearly sought to imbue his approach to international relations with his deal-making persona.

It took just one week for Trump to create—and then resolve—the Greenland crisis. Over the course of a week in January, he followed the strategy laid out in his book almost line by line.

Trump’s signature negotiation tactics can be distilled into 5 key rules. They are:

Rule 1: Aim high

Rule 2: the BATNA