This qualitative study analyzed the meaning-making practices of urban adolescents participating in a college preparatory program featuring philosophical inquiry into cosmopolitanism and the creation of multimodal texts. In contrast to studies of composing that focus on individual outcomes, this dissertation traced group meaning making. The study was grounded in sociocultural perspectives that theorize literacy as diverse, socially constructed, meaning-making practices that emerge in particular cultural and social contexts, and include multiple modes of communication. Data included interviews, observations, and artifacts. To analyze the data, a music-inspired analytic system was devised to examine the collaborative nature of composing. The study demonstrated, first, that composing in this setting was a collaborative process exceeding customary understandings of collaborative composing. Uncovered after examining complex patterns of interactions over varied timescales, collaboration at the group level occurred while community members created individual products. Second, the study revealed that improvisation was an important strategy for shaping the content of this collaborative process. During informal jam sessions, participants creatively explored options for representing content. They actively built upon ideas offered by other participants in the moment, in order to read, interpret, select, and design the content of their multimodal texts. Last, facilitated by the complex patterns of interaction and shaped by the improvised frames for representing content, this study revealed the ways in which participants constructed a shared meaning of the concept of cosmopolitanism at the group level. Utilizing an image-afforded exploration of juxtaposition, this shared understanding evolved from early conceptions of cosmopolitanism as represented in juxtaposed images to an understanding of cosmopolitanism as the act of creating and interpreting juxtaposition between varying perspectives. This study contributes to growing empirical research on meaning making through multimodal text design. It extends socio-cultural explanations of what counts as "social" in educational contexts, illustrating that composing is not just influenced by social interaction but rather "is" social. Finally, in an age of standards, testing, and accountability that can narrow what constitutes valued literacy practices, this study provides an example of the varied interactional paths and diverse compositional strategies and products that can engage learners and expand opportunities for meaning making. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]