Halford Mackinder has had a posthumous existence that many of us might envy. Long after his earthly demise, some of his ideas, particularly that of the “geographical pivot of history,” keep coming back to life. Currently, some well-known pundits in US foreign-policy circles, typically thought of as neo-conservative and keen on a “muscular” US military presence around the world, have re-discovered Mackinder’s geographical determinism as providing a seemingly naturalistic account for the approaching rebirth of the “yellow peril” (the rise of China) and offering as it did at the turn of the last century a timeless rendering of the challenges to the democratic maritime powers from the despotic land powers of Eurasia. The widely cited American journalist Robert Kaplan (2010: 22), for example, frames the emerging “geography” of China’s power almost entirely in these terms. It is timely, therefore, to have a new intellectual biography of Mackinder that not only critically engages with the central themes of his geopolitics but that does so by both situating them in the historical context of the early twentieth century and showing why they remain attractive in some quarters by dint of their effective depoliticization of the very world politics that they underwrite. This book matters, therefore, in a number of distinctive ways. That was why a session devoted to it was so worth organizing at the Washington DC AAG Annual Meeting in April 2010. When I first heard from Gerry Kearns that he was planning to write a book focused on Mackinder and his geopolitics I must admit to having been less than enthusiastic. I have spent some time and energy down the years trying to expropriate the word “geopolitics” for uses other than those ascribed to Mackinder and his ilk of early twentieth century imperialists. But I erred. Gerry has done much more than write a conventional biography of Mackinder. A very serviceable one by Brian Blouet (1987) already exists. The various commentaries that follow this Introduction outline what the book does across the course of its nine chapters. More critically they also show how the book contributes to our understanding of both why it was Mackinder’s ideas and not those of some contemporaries that tended to win out and why these ideas have had a continuing resonance, particularly in policy-making circles in certain foreign ministries, years after the immediate historical context in which Mackinder lived has long disappeared. What is important to emphasize above all as its leitmotif is that this book is illustrative of a successful use of the biography of a singularly influential geopolitical thinker to show how alternative geopolitical scenarios and futures have always been and still are possible. Mackinder never used the word geopolitics. Yet, at least in the English-speaking world, it is to him and a couple of other writers from around his lifetime (Mahan, for example) that the term is frequently ascribed. In lodging the geo into politics as a causal term, the compound word conveys exactly the combined sense of geographical determinism and prophetic understanding to which the geopolitician aspires. He (it is almost always so) tells us what is determining and, presumably, in having this expert knowledge, can warn us (those of us on the wrong side of the geography) before it is too late. The contradiction here, of course, is that if we can aspire to do something in the face of geographical determinism then the determinism cannot be absolute but must be also contingent in its effects. Obviously, noting such irony was not Mackinder’s strong point, neither is it of his apostles. Gerry Kearns fills us in on how this happened and, more importantly perhaps, on how it can be exploited to create a very different approach to geopolitics in which it is the very contingencies of political economy and geopolitical imagination that become its determining elements.