This paper presents the methodological framework that we developed for collecting, studying and passing on tacit and explicit know-how embodied in the professional gestures of expert workers. This framework is based on the adaptation and combination of a range of psychological theories and techniques: the Activity Theory, the ‘Perceived Quality’ approach, Subjective Evidence-Based Ethnography, and verbal protocols. The application of the method, which focuses primarily on the perspective of the expert, has enabled us to build a cognitive model of the professional gesture to be transmitted, by highlighting its key points. It has led to the development of multimedia training products called MAPs (Multimedia Platform for Apprenticeship) designed to “represent” and convey knowledge involved in the real-time performance of the expert’s gesture. The methodology was developed and applied to manual operators, in actual work and training settings in the largest French power company. The practical aim of the study was to address an organisational issue of knowledge management, for professional training purposes, in order to bridge the gap in learning through mentoring between retiring experts and novices. The method has recently been implemented throughout the company in which the research was carried out and could be applied to many other situations and contexts.