Current research on e-journal usage patterns focuses more on measuring levels of use and measuring changes in reading patterns than developing theoretical models that enable the explanation and prediction of patterns in the adoption and uptake of e-journals across scientific fields. Typically, studies either focus on single disciplines or attempt to reach an overview of disciplinary differences by using broad disciplinary groupings, such as physical sciences, health sciences, applied technologies, social sciences, or humanities. We argue that there is a need for extending the domain analytic approach to incorporate a fuller understanding of the cultural characteristics of scientific specialisms, which include both epistemological and social considerations. To this end we suggest that Whitley's theory of the social organization of scholarly fields can be effectively used as an explanatory model of e-journal use across scientific fields. By using Whitley's theory we also illustrate the limitation of current approaches to the explanation of information practices and e-journal use that use the administrative unit of the discipline, or base comparison on coarse-grained aggregations as the unit of analysis, rather than the specialism.