The theatre of Roblès, perhaps best known in this country for Montserrat, includes dramatic comedy and farce as well as tragedy, examples of which are included in this first selection in Eng­lish.     Outside the community of scholars of French studies, Roblès, whose works have not only won a number of literary prizes but have also placed him in the select membership of the Goncourt Academy, is relatively unknown in the English-speaking world. It is safe to say that Roblès’s theatre is better known in Iron Curtain countries than in the United States, a lack that this authorized translation of the three representative plays included here seeks to remedy.   The tragedy, Case for a Rebel, the dramatic comedy, The Clock, and the farce, Porfirio, represent Roblès’s versa­tility in the diversity of genres. As an anthology intended for the reading public and for students of drama, the three plays illustrate an important factor in the dramatist’s aesthetic: his profound commitment to fellowman and his hatred of oppression. All three plays portray oppression in its various manifestations.   Since the mid-1930s Emmanuel Roblès has combined writing and teaching with extensive traveling. He resides part of the year in France and part in Algeria, the country of his birth.