The aim of this article is to put Torsten Hagerstrands contribution to the development of the activity approach in transport geography into the context of his development of time-geography as an integrative ecological world view. This is discussed from a biographical perspective where experiences in his everyday life and scientific investigations are linked into a theoretical whole. The theoretical approach of Hagerstrand can be traced to experiences several years before he presented his time-geographic approach. He studied conditions for individuals existence in different geographic, social, and ecological contexts by engaging new methods and cross-fertilizing research fields; he developed precise concepts and a notation system general eno...