The workshop introduced by this text is a visit of the questions and experiments which, in the Seventies, led the author to conceive that his research of didactic engineering could not continue without suitable theoretical reflections which were to be supported by new experiments. Along the promenade in this labyrinth, the author passes from questions of epistemology to the inventory of materials available, then from the search for models of situations with the evocation of the famous quarrel of the learning models, to the bases of the theory of the mathematical situations. He visits thus various sectors of mathematics education, like Euclidean division or the introduction of probabilities. This workshop prolongs the methodological reflections which were undertaken in EEDMXIII about « Didactic engineering and analysis of the didactic processes », in which the author studied, in precise way, the problems of didactic engineering that appear in the research about the teaching of a mathematical topic (Ex.: rational and decimal numbers). A third text has to be add at this two: a presentation of the conditions (technical and mainly deontological) which drove the COREM to produce these processes.