This book focuses on the dynamic nature of EAP (English for academic purposes) learners' beliefs about language learning in their shift from an EFL (English as a foreign language) environment to an EMI (English as the medium of instruction) setting in mainland China. It adopts a mixed method paradigm, whose quantitative part aims to capture the general dynamic feature of the selected student population, while its qualitative part attempts to unveil the process of change in beliefs about language learning among the sample. It is hypothesized that the change in their beliefs about language learning is the result of the interplay between the learners' agency and the mediation of the contextual realities at the institutional and social levels.