This study employed two distinct methodologies: 18 months of participant observation whilst working as a nurse and invited observations of episodes of skilled behaviour followed by knowledge interviews using heuristic devices as mediating artefacts. Access to the ward and invitations to observe (with patient consent) were granted in return for free labour between episodes and whenever the ward was exceptionally busy. The ethnographic data was analysed using Strauss’s paradigm analysis; the resultant accounts of ward activities, culture and performance were checked by participants. Two forms of mediating artefact were used to facilitate knowledge elicitation interviews and the co-construction with practitioners of representations of their expertise. The first was a small knowledge map linking scientific knowledge to nursing interventions and processes, sketched immediately after observation; this followed the format developed by Eraut. The second was a sequence of digital photographs taken during the episode itself, subject to immediate censorship by the patient. Post-interview accounts of the episode, supplemented by revised maps and relevant photographs, were checked by the practitioner on the following day. The 52 accounts were then analysed according to type of task, degree of fluency, use of deliberation, nurse’s levels of experience, situational recognition and degree of guidance provided by anticipated outcomes. The dual methodology provides a unique perspective on factors affecting access to learning opportunities and the relationship between individuals learning and transactions within the context of everyday practice. Subsequent publications will further discuss the progressive development of nursing expertise, illustrating the following: the role of disposition towards learning of capable practitioners; whether learning was facilitated or constrained by the system of work allocation on the ward; learning and individual dispositions towards the constraints of context, and the role of historical camps, loyalties and allegiances in promoting domain traditions in nursing work.