Information literacy, 40 years since the term was coined, remains a conceptually contested aspect of library and information science research. This paper uses a review of the literature related to the concept of information literacy to identify three different perspectives, their historical origins, and connection to library and information science practice. The three conceptualisations we identify from the literature are: 1) information literacy as the acquisition of "information age" skills, 2) information literacy as the cultivation of habits of mind, and 3) information literacy as engagement in information-rich social practices. The goal of this synthesis is the creation of a stronger, more united field of study, as well as a clearer alignment between information literacy and the formal and informal contexts where people employ and develop information literacy. [This paper was published as part of: Proceedings of the Eighth International Conference on Conceptions of Library and Information Science, Copenhagen, Denmark, 19-22 August, 2013.]