The Isis Current Bibliography has been in existence for 100 years. It was one of the foundations upon which the discipline of history of science was built, especially in the eyes of its founder, George Sarton. Up to now, there have been no careful studies of the actual use of the bibliography, and this paper seeks to explore data from a survey of historians of science that will be conducted in the spring of 2013 regarding the nature of usage of the Isis Bibliography. The present moment presents a particularly interesting time for measuring usage because we are at a nexus between two radically different kinds of research environments, one based on print and the other based on digital forms. Most scholarship these days is of some hybrid nature. Moreover, the Bibliography exists in three distinctly different formats, one print and two electronic, and it has had a digital presence for over twenty years, which means that scholarly use of the digital format has had a chance to become well established over that time. The survey of users will be able to explore ways in which digital tools and print tools are differently used, and will analyze disciplinary and demographic differences in the types of research conducted. Because scholars are frequently also teachers, the survey will also explore ways in which the Bibliography has been used in educational settings. The survey will make a careful attempt to differentiate institutional affiliations, so that education and research missions of institutions can be taken into account. In the end, we expect to be able to see patterns of use that will indicate how the digital, networked information environment has changed and is continuing to change the ecology of knowledge in the discipline. Since the Bibliography has played a central role in the disciplinary formation of the history of science community, we will also be looking for evidence about how that role has changed and developed over time by studying historical evidence in relationship to the survey results.