This is the first substantial commentary on Clouds since Dover's 1968 edition. Intended for intermediate Greek students at undergraduate and graduate levels, the commentary pays careful attention to the basic characteristics of ancient Greek syntax, as well as to how Greek words are formed and can be analyzed. It offers robust staging notes, information about daily life in late 5th-century Athens, and constant reference to the rhetorical and dramatic strategies of the text. Full support is offered for those interested in the metrical structure of the songs, but in a way that allows instructors to leave such issues aside, should they choose to do so. The first and second appendices offer a basic means of entry into the rich but complex world of the comic fragments. An English-language bibliography is provided. The edition will interest professional classicists of all sorts seeking an accessible introduction to one of Aristophanes' greatest plays, to philosophers concerned with Socrates and the sophistic movement, and to theater professionals who wish to stage the play.