Unlike previous research, which tended to exclusively conduct expert/user evaluation and rely heavily on subjective survey data for simply ascertaining general satisfaction with a fixed predetermined set of coursebook features, this multimethod study sought to provide a holistic, multidimensional and thus more realistic assessment of coursebook performance through conflating objective information on its compositionality with reflective user knowledge about the actual functioning. Therefore, we used the inputs-processes-outcomes (IPO) model for the deconstruction of a global coursebook in dental English, based the expert review on corpus findings and complemented it with the less-studied student-users’ (87 sophomores from a Turkish-medium dental school of a large urban public university) retrospective evaluation against preferred criteria. The corpus-based IPO analysis of the coursebook (non-)texts and content analysis of their post-use reflections revealed that the students, with a mildly positive orientation, were more concerned with: the scope of content-knowledge, visuality and text quality presented by the inputs; amount and nature of language practice, opportunities for oral fluency development and independent learning, and also acquisition of disciplinary vocabulary triggered by the processes, whereas the material proved efficient for: making core content accessible by pedagogically-prepared non-argumentative texts, introducing an egalitarian style of communication through created dentist-patient dialogues, ensuring ample practice in a non-threatening atmosphere with the right blend of pre-communicative and loosely-controlled communicative activities, developing formulaic sequences essentially for workplace transactions, building a carefully-selected repertoire of high-frequency dental words and teaching vocabulary directly with true-to-life photos. To achieve deeper learning outcomes than functional language mastery, it still needs transformation through: learner-compiled (e-)portfolios of academic and humorous genres, increased visibility for women dentists, creative use of illustrations, integration of cross-cultural elements, conscious attention to grammar and ludic language use and incorporation of service-learning projects on linguistic/cultural mediation.