The Organization of the Petroleum Exporting Countries (OPEC) is one of the most recognizable acronyms among international organizations. It is mainly associated with the “oil shock” of 1973 when the price of petroleum increased fourfold and industrialized countries and consumers were forced to face the limits of their development model. This is the first history of OPEC and of its members written by a professional historian. It carries the reader from the formation of the first petrostate in the world, Venezuela in the late 1920s, to the global ascent of petrostates and OPEC in the 1970s, to their crisis at the end of the 1980s and beginning of the 1990s. Born in 1960, OPEC was the first international organization of the Global South. It was widely perceived as acting as the economic “spearhead” of the Global South and acquired a role that went far beyond the realm of oil politics. Petrostates such as Venezuela, Nigeria, Algeria, Saudi Arabia, Iraq, Iran, have been (and still are) key regional actors and their enduring cooperation, defying wide political and cultural differences and even wars, speaks to the centrality of natural resources in the history of the twentieth century, and to the underlying conflict between producers and consumers of these natural resources. Being the first study to use previously unavailable OPEC sources, it offers surprising insights into the way of thinking of the ruling elites in petrostates and to the way the world looks when seen through their eyes.