Using life-history interviews on a sample of Swedish inventors, this article studies seminal sociocultural factors and milieus that are critical for the development of inventive capacities. This approach allows the inventors to reflect on and describe the milieus, actors and events in their lives which they themselves believe have formed their inventive capacities. The main findings of the article are that the sociocultural milieus of early childhood, especially the educational backgrounds or skills of parents and grandparents, play an important role in shaping the anatomy of inventors. Further, the social milieu of an inventor’s final education, whether elementary school or university, is a seminal factor in the development of inventive creativity, given the importance of dedicated teachers, co-students and supervisors. Finally, egalitarian organizational structures in the workplace and a solid knowledge infrastructure are also important and influential factors. The study shows that the essence of these seminal milieus varies for different types of inventor, hence three descriptive ideal types of inventor are presented, namely the workshop inventor, the engineering inventor and the academic inventor.