In the world of Chicana fiction, Ana Castillo has achieved the kind of status Maxine Hong Kingston has attained within Asian American discourse. Castillo's work is popular not only with the general reading public but in many academic circles as well. What sets Castillo apart from so many other Chicana fiction writers is that she is also a theorist, and her "Massacre of the Dreamers: Essays on Xicanisma" (1994) has achieved widespread acclaim. In "Massacre of the Dreamers," a collection of critical essays on the experience of those whom Castillo calls "Mexic Amerindians," Castillo suggests rather explicitly that, while Chicana identity is fragmented due to the vicissitudes of history, there is an essential "Mexic Amerindian" identity that can be "asserted." In order to illuminate the ways in which Castillo theorizes and constructs Chicana identity, the author looks at the relationship between Castillo's own theoretical work, "Massacre of the Dreamers," and her fiction, including "The Mixquiahuala Letters" and "So Far From God." He argues that there is a curious incongruity between how Castillo theorizes the Chicana subject and how her characters perform subjectivity in her fiction. While Castillo's fiction not only exemplifies and performs "the arcane mysteries of absence, trace, and the slippery possibilities of presence" that are the hallmark of postmodernism, in "Massacre of the Dreamers" Castillo nostalgically searches for an originating moment that will ground her Mexic Amerindian identity (Smith 6). In this article, the author looks first at the important ways Chicana/o theorists Gloria Anzaldua, Chela Sandoval, Emma Perez, and Guillermo Gomez-Pena theorize the Chicana/o subject and the ideological terrain in which it circulates before going into the details of Castillo's work. (Contains 16 notes.)