We propose to provide lines for thought regarding gathering of information by professionals, and the importance of their inclusion in training situations. This paper results from two researches in professional didactics: the first one, focuses on the activity of farmers who use chipped ground to fertilize their soil, the second one, focuses on the use of a Computer Numerical Control Machine in professional situation and training situation. We show that information gathering is both source and product of the professionals' representations for action. We propose theoretical and methodological proposals concerning the gathering of information. Finally, we show that focusing on the gathering of information is useful to analyze the activity in professional situation, the activity in training situation, and the relationship between these two situations.
