This book highlights the importance of English academic vocabulary for success at university and explores written tasks as effective pedagogical tools to promote the acquisition of academic words. The book reviews germane and recent SLA, psycholinguistic, corpus linguistics, and L2 writing research to underscore the challenges associated with the learning of academic words. Then, it reports on three empirical studies conducted in the Polish context. The first study develops a reliable tool to assess the knowledge of academic vocabulary of undergraduate learners. The second and third studies investigate the learning of academic words after the writing of sentences and argumentative essays, and discuss the role of cognition as a mediator of such learning. The book also provides an accessible introduction to linear mixed-effect models, a powerful, reliable, and flexible statistical technique that has been gaining popularity among SLA and psycholinguistics researchers.