This book challenges widespread academic and media claims that Russia and Belarus are unwavering allies or that Russia has unquestioned control over Belarus. Instead, Belarus plays at least four different roles within Russian foreign policy. First, Belarus is sometimes a conduit for Russian power projection towards Western enemies. Second, Belarus is sometimes a supporter in Russian attempts to centralize the post-Soviet space around itself. Third, Belarus is sometimes itself an object of Russian economic ambition or even greed. Fourth, however, Belarus also presents a source of danger and vulnerability to Russian physical and, perhaps more importantly, ontological security. Many scholars have pointed out the historical and contemporary importance of Ukraine for Russian self-understanding and external projection. Belarus, too, has such importance. Whether it be as a millennium-old "grey zone" between Russia and what it saw as its ideological and military enemies, or whether it be as the place where the "most perfect" Soviet republic was created, the Belarusian lands today present themselves to Russia simultaneously as open to the passage of alien subversive influences and as a place claiming to be the real heir to Soviet victory and to Slavic purity - both mantles otherwise claimed by Russia.