The 2022 Russian invasion of Ukraine represents for Putin what the crossing of the Rubicon represented for Julius Caesar in 49 BC. After making this decision, Moscow can never go back. With this critical choice, one of the most significant since the end of World War II, Russia has decided to accelerate the course of history. In its attack against Ukraine, Putin's Russia confirmed its role as a revisionist power and challenger of the international order, deciding to operate outside the rules set in the post-1945 and post-1991 world system. The arrival point of the historic process will have two possible consequences for the international system: either the confirmation of the hegemonic role of the US-led West or the advent of a centrifugal multipolar world. War in the Borderland: Four Ways to Interpret the Conflict in Ukraine examines the reasons why the Russian-Ukrainian war broke out, highlighting four possible interpretations. Specifically, by examining the domains of geopolitics, geostrategy, geoeconomics, and ideology, the book aims to determine how these variables played an important role in the outbreak of this gruesome conflict.