This chapter reviews some of themost important human dimensions applicable to the design and use of information spaces, with a focus on library applications. The chapter begins with an introduction to the area of information spaces, presenting an established view of human information processing that can be used to understand the way in which users make sense of information that is presented to them through information spaces. Designing effective systems that allow access to information spaces is a complex problem and there has been substantial research into the area. This chapter will turn to describing a set of well-established principles,drawn from the work of Norman (1988), that views consistent and well-grounded design as a key issue in alleviating problems of use by considering design in relation to users. To this end, a design case is presented to explore user task scenarios with respect to a particular library application, thus illustrating the emerging usability issues as they relate to interface design features. Notwithstanding the importance of the high-level design principles, the diverse background of the individual users accessing information spaces are not necessarily acknowledged or addressed. The chapter will therefore go on to present an analysis of what are argued to be the most important individual differences that can influence the way that users interact with systems and make sense of the information that they encounter. Finally, the chapter will consider the design of information spaces to allow for their context of use in terms of issues related to devices and mobility that are likely to become increasingly important in the coming few years for the provision of information spaces and the electronic library interface.