The present volume contains a selection of papers presented at the Fifth International Symposium Russian Grammar: System-Usus-Language Variation, from September 22 to 24, 2021, at the University of Potsdam (Germany). The selected essays tackle the issues that arise when Russian Grammar meets new linguistic paradigms (such as corpus linguistics) and new challenges (such as heritage languages). The relevant findings are discussed with a particular focus on an updated version of the 1980 Academy grammar of Russian.