I write a math textbook for which I want to make an overview chapter for each part of the textbook. In those overview chapters I want to motivate and introduce the new mathematical concepts. I also want to answer questions like: Why do we need those mathematical concepts? How did the concept evolve in history? What will be the content of the next chapters?
In this context, will the overview sections facilitate learning? How important are overview chapters in textbooks for the success of learning? Is there any research about it?
Note: I asked the same question on cogsci.stackexchange.com. Since I haven't got an answer there I want to reask this question here. I hope that's okay.