摘要:The aim of this article is to discuss questions related to a qualitative investigation in a longitudinal perspective. The empirical basis of the investigation was a study developed in Portugal concerning the nature, the processes, and the contexts of learning and of professional development of teachers in the first two first of the activity of teaching. The article discusses as well some aspects associated with the methodological options that were taken in the investigation, with the epistemological problem of validity and relevance, with the role of the investigator, and with the ethics of the investigation.