Alarconian criticism has been given direction largely by Pérez de Montalbán's remark about the dramatist's extrañeza; consequently, much attention has been addressed to the spirit of his work—his philosophy, his moral concepts, his characterizations, his mexicanismo—but relatively little to the structure of his comedias. Thus the mechanical elements of Alarcón's plays have been largely neglected, this neglect apparently arising from the belief that in the matter of structure Alarcón relied heavily upon his masters Tirso and Lope. I have made some preliminary studies of the structure of the Alarconian comedia, and my examination of this subject reveals that in at least one respect Alarcón was demonstrably independent of these masters. The letter which is read aloud on the stage clearly illustrates how the poet departed from the practices of his contemporaries; in point of fact, the letter proves significant since a comparative study of Alarcón, Tirso, and Lope shows special patterns to be distinctive of each of these poets.