Increasingly, International Relations (IR) theorists are drawing inspiration from a broad range of theorists outside the discipline. One thinks of the introduction of Antonio Gramsci's writings to IR theorists by Robert Cox, for example, and the ‘school’ that has developed in its wake. Similarly, the works of Anthony Giddens, Michel Foucault, and Jurgen Habermas are all relatively familiar to most IR theorists not because of their writings on world politics per se, but because they were imported into the field by roving theorists. Many others of varying success could be cited as well. Such cross-disciplinary excursions are important because they inject vitality into a field that – in the opinion of some at least—is in need of rejuvenation in the face of contemporary changes. In this paper, I elaborate on the work of the Canadian communications theorist Harold Innis, situating his work within contemporary IR theory while underlining his historicism, holism, and attention to time-space biases.