This paper deals with a course intended to teach individuals a method of convergent thinking, or "idea focusing", in seeking inventive solutions to problems and designing innovative artefacts. The course participants (mathematics, science, or technology teachers) learned a range of "inventive principles" often used for problem-solving in scientific and technological environments. The research method combined quantitative and qualitative methods, such as observations, pre-post course quizzes, and interviews, aimed at collecting as much information as possible on students' activities, achievements, and attitudes during the course. The results indicated that the participants gradually increased their confidence in utilising the method and combined several techniques in solving a problem. They also increasingly recognised that many inventive ideas are based on simple principles that can be learned and applied in diverse contexts. The question of introducing the learning of inventive problem-solving into the school curriculum, however, requires additional research. (Contains 3 figures.)