For a good orientation into the history of English grammar, several books are indispensable. One of those is Mustanoja’s A Middle English Syntax. However, for a long time this work was not readily available; the present edition changes that. This is a fac simile reprint from the 1960 publication which appeared as volume XXIII in ‘Mémoires de la Société Néophilologique de Helsinki’, with a new Introduction by Elly van Gelderen. Compared to Old English, Middle English has fewer grammars and textbooks devoted to it. This book provides an interesting supplement by going deeper into certain questions and, especially, into exceptions. The book points out differences with Old English and certain peculiarities of the Middle English system. It was originally written for students of Middle English literature but serves a linguist well in detailed descriptions of the parts of speech, the use of the various cases, gender, and number. Word order, complex sentences, and conjunctions were meant to be dealt with in a second volume, which was never published.