Beginning in the late Middle Ages and up through the beginning of the twentieth century, it was perfectly normal for children to get an education or be trained in a profession by being apprenticed to masters in their workplace. The apprentice began by observing the master craftsman at work--for example a weaver, blacksmith, or printer--and learned to look and practice under her or his (almost always his) tutelage. The training was mostly about practical actions; the usefulness of what had to be learned was clear, and there were clearly defined end products such as a cloth or tapestry, a knife, or a book. Also, the learning environment was social. In their article, "Cognitive Apprenticeship: Making Thinking Visible," (available at https://www.aft.org/ae/winter1991/collins_brown_holum) Allan Collins, John Seely Brown, and Ann Holum make a case for a form of instruction that resembles the former master-apprenticeship relationship. They call this method of instruction "cognitive apprenticeship". Cognitive strategies are central to the integration of skills and knowledge and certainly to abstract knowledge areas such as reading, writing, and arithmetic. These strategies are, in their view, best communicated through contemporary apprenticeship education: learners should see from an expert (teacher or more advanced fellow student) and hear how they solve the task, which strategies the expert uses, and why. The student can then practice under supervision.