In 1887 Halford Mackinder was appointed Reader in Geography at the University of Oxford. Although for centuries aspects of what is now considered to be geography had been taught across a range of subjects, from astronomy to geometry, mathematics languages, philosophy and religion, this was the first position dedicated to geography at one of the ancient English universities. Mackinder is also known as the father of geopolitics. However, this talk approaches the study of Mackinder as an ongoing project and a subject to which historical geographers have brought their varying and spatially and temporally attuned attentions. It argues that became a geographer, initially by studying anything but geography as, throughout his career, from his Oxford University Junior Science Club lectures to his early University Extension teaching, Mackinder relied on popular methods as well as popular science. He, moreover, consistently dedicated his energies and time to furthering geography education at all levels and widening the geographies of geography education. Arguably, he was most successful in popularizing knowledge across a range of venues and accessed by diverse publics, as well as encouraging greater transdisciplinary exchange between the then diverging sciences and humanities subjects. In such ways he can be seen to have served the history and philosophy of science.