Today's readers of scholarly literature want to read more in less time. With this in mind, this study applies the idea of the functional unit to the use of digital documents. A functional unit is the smallest information unit with a distinct function within the Introduction, Methods, Results and Discussion components of scholarly journal articles. Through a review and analysis of the literature and validation through user surveys, this study identifies a set of common functional units and examines how they are related to different tasks requiring use of information in journal articles and how they are related to each other for a particular information use task. The findings, presented in the form of a taxonomy, suggest a close relationship between functional units and information use tasks, and furthermore among a set of functional units for a particular information use task. This taxonomy can be used in the design of an electronic journal reading system to support effective and efficient information use.