This paper reports a work in progress to investigate the current and intended future use of open digital textbooks in Irish higher education. It begins by establishing that open digital textbooks, as a subset of the wider Open Educational Resources (OER) movement, have not featured prominently in Irish higher education policy texts. A brief synthesis of the macro-level literature reveals the strong North American influence driving innovations in open digital textbooks over the past decade, particularly in response to increasing concerns about rising costs. At the mesolevel the research problem is framed by a gap in the literature and lack of information more generally about textbook use in Irish higher education, although more specifically the study aims to establish current and intended future usage of open digital textbooks. Five research questions that guide the study are then outlined along with the methodology for the first two parallel work packages: (a) an environmental scan and national baseline survey of open digital textbooks in the Irish higher education sector; and (b) a micro-level institutional case study of current practice around the use of textbooks and adoption of open digital textbooks more particularly. The final work package aspires to develop an open digital textbook initiative based on findings from earlier phases and the international literature. While the study is still at an early stage a critical perspective underpins the research as we seek to better understand the potential transformative advantages of open digital textbooks over and above the use of more conventional learning resources.