In a lifelong journey of self-conscious reevaluations the Swedish geographer Gunnar Olsson has pursued his core theme of human interaction in search of its geographical essences. Marked by a refusal to limit his geography to the study of visible things, Olsson has developed an original yet consistent cartography of how humans find their way into the unknown by relying on cultural maps which treats the invisible as if it were visible. What unfolds in his geography is an understanding of modern reason as a form of cartographical reason founded on a taken-for-granted geometric coordinate net of lines, points, and planes. Preceding a critique also of his own approach, he recognizes that this is also a reason which is becoming increasingly outdated, although it is likely to continue to haunt us as well as human geography.