There is always a dark side, and taxation in its international dimension is no less. Pecunia, being the cash, drives it more than philosophical principles like justice or solidarity. International taxpayers, whether individuals or corporations, do not feel the same obligations vis à vis the society where they temporarily live, work and produce their wealth as if they would feel if they were permanently integrated in a country. The reader of this textbook will be conducted within the technicalities of international taxation by way of an original perspective on philosophy, politics and economics (PPE) affording (i) who has the right to exercise the power to tax by examining the criteria to determine the jurisdiction to tax both in the worldwide and territorial system, (ii) how to exercise the power to tax, through tax return or withholding tax, (iii) what to tax among active and passive income within inbound and outbound taxation, (iv) how much to tax through the transfer pricing, (v) international taxation as part of international law, (vi) international tax treaties, and finally (vii) the BEPS projects that represent the very last evolution in the field. Scandals, leaks as a James Bond movie, aggressive tax planning techniques and related case law, involving high-net-worth individuals as well as multinational corporations, bring the reader to discover that each single State belonging to the international community acts as a chess player before the international tax chessboard observing as pieces its own economy, its own society, and balancing any tax policy decision with possible reactions of domestic taxpayers that could move away, those foreign taxpayers that could decide to move in, and possible retaliations from other States. The ambition is to get the reader convinced that, as the Sicilian Tancredi Falconeri warns his uncle Don Fabrizio Corbera, Prince of Salina, in the masterpiece book “The Leopard” of Giuseppe Tomasi di Lampedusa, “everything must change because everything remains as it is”, and only exploring what is behind the stage of international taxation clarifies how this important piece of social science really works.