ABSTRACT
The study addresses the problem of how to characterize individual workers’ development while they are engaged in a work activity that is changing. The site of study was a machine shop. Machining work has undergone rapid technological changes, with many of the changes occurring within the working lives of individuals. The work expands our understanding of cognition and shows it as multifaceted, embodying knowledge and skill, as well as identity formation. The work also contributes to a better understanding of how knowledge and skills generalize from one situation to another.