Bosnian, Croatian, Montenegrin and Serbian: An Essential Grammar is intended for beginners and intermediate students who need a reference that explains grammar in straightforward terms. It covers all the main areas of the modern single BCMS grammatical system in an accessible way, and free from jargon. When linguistic terminology is used, it is explained in layman's terms, the logic of a rule is presented simply and near parallels are drawn with English. This book covers all the grammar necessary for everyday communication (reaching B1 and B2 of the CEFR, ACTFL Intermediate-Intermediate- Mid). The book comprises of extensive chapters on all parts of speech, the creation of different word forms (endings for cases in nouns and adjectives, case forms for pronouns, tenses, verbal modes, verbal aspect etc.) and their uses in sentences. Each rule is illustrated with numerous examples from everyday living language used in Bosnia-Herzegovina, Croatia, Montenegro and Serbia. This is a unique reference book in English aimed at the level of language study that treats BCMS as a single grammar system, explaining and highlighting all the small differences between the four variants of this polycentric language.