Writing from sources is viewed as a fundamental component of academic literacy as well as developing connections between reading and writing. An especially challenging task of source-based writing is synthesizing, which requires careful selection, organization and integration of sources. Given the significance of synthesizing in developing multilingual students' academic literacy in English, this study examined the teaching and learning of synthesis writing in a university L2 composition course. Within a multidimensional view of literacy and discourses of writing, I conducted classroom-based qualitative multiple case studies, in which both the teacher's experience with synthesis instruction and four Chinese undergraduate students' engagement in synthesis writing were examined. Guided by the constructivist model of discourse synthesis - organizing, selecting and connecting (Spivey, 1990, 1997) - from the L1 composition literature, I investigated the teacher's task representation of synthesis, the students' developmental trajectories of learning to write a synthesis, and the individual and contextual factors that contributed to their varied writing abilities while approaching synthesis tasks. Citation reproduced with permission of ProQuest LLC. Abridged abstract reproduced with permission of ProQuest LLC. Full text available at URL below.