This book delves into the resurgence of China and Russia as assertive regional powers, igniting debates and renewed interest in the dynamics of great power politics and power transitions. The questions of how competition with these states will evolve and what the future international system may resemble given their potential regional dominance are at the forefront of global concerns in the coming decades. As power politics intensify, the significance of allies and alliance systems escalates, becoming critical tools for states seeking to navigate this rising great power competition effectively.