Members of a site of the California Writing Project conducted the study in this article in partnership with a large, urban, low-SES school district where 93% of the students speak English as a second language and 69% are designated Limited English Proficient. Over an eight-year period, a relatively stable group of 55 secondary teachers engaged in ongoing professional development implemented a cognitive strategies approach to reading and writing instruction, making visible for approximately 2,000 students per year the thinking tools experienced readers and writers access in the process of meaning construction. This article describes the final year of the project which addressed teaching students to understand, analyze, and write interpretive essays about theme. Students who received cognitive strategies instruction focused on theme significantly out-gained peers on holistically scored assessments of academic writing, on a high stakes statewide writing assessment, and on English placement exams at the local community college. (Contains 2 figures and 5 tables.)