This is the first detailed descriptive grammar in English (indeed, in any language other than Japanese) dedicated to the Western Old Japanese, which was spoken in the Kansai region of Japan during the seventh and eighth centuries. The grammar is divided into two volumes, with the first volume dealing with sources, script, phonology, lexicon and nominals. The second volume focuses on adjectives, verbs, adverbs, particles and conjunctions. In addition to descriptive data, the grammar also includes comparisons between Western Old Japanese and Eastern Old Japanese and Ryukyuan, together with a critical analysis of various external parallels.