Much of the appeal of realism stems from a belief that it's more grounded in reality and pragmatism. In this way, it's often the bias of choice for academics simply because it makes one's ideas appear more legitimate. Here's a case in point: Carr spends nearly the entire book ripping apart utopianism and pluralism, as any "good realist" would be apt to do, only to reach the last chapter where he declares liberalism is the only hope for mankind. So it's clear that he wasn't really a true Realist, but used it for improving his career prospects. It obviously worked, because The Twenty Years' Crisis is considered a classic work in realism. Nonetheless, Carr comes up with some great insights. He correctly predicts the rise of nonstate actors. Though he is wrong in thinking colonization would continue for the long haul in its current form, yet he predicts the move away from expansionism in favor of interchangeable puppet governments and international subversion. Carr has great advice when he says war will continue until nations begin sacrificing for one another, something that U.S. actions in Latin America and the United Fruit Company fiasco chose to disregard. My favorite point is when he says absolute peace is only possible when there is a larger, common threat that subunits can mobilize against. Earth cannot unite against the impending threat from the Planet Mars, for instance. Well, maybe there are no Martians, but perhaps there's someone else out there...