This dissertation uncovered how a group of second language (L2) students, including international and immigrant students, became socialized into American academic discourse through the writing that they did as graduate students in the context of their academic field. In particular, this study focused on Mandarin Chinese-speaking graduate students studying in an M.A. program of Teaching English to Speakers of Other Languages (TESOL) at a major U.S. university located in the Bay Area of Northern California. This study used a combination of writing research methods--case study techniques of interview and document collection, combined with discourse and text analysis of students' oral and written language--within a socio-cultural/historic theoretical frame. This study revealed that even within one language group learning to write in a particular field, there is great variety among the students in terms of their writing perspectives and performances, struggles and strategies, as well as participation norms and membership negotiation in their academic/professional discourse community. Further, the students' differing perceptions/perspectives reflect the different social and writing experiences that they bring to their new learning and living contexts, with ambivalence and tensions inherent in their academic literacy practices that show their individuality as well as group membership. This study also revealed the TESOL community a complex and varied one, allowing different kinds of written participation that (re)define the students as they engage in writing and other related activities in their course(s). Implications and recommendations for the areas of theory, research, and teaching are also discussed.