It is not obvious how to write a book. I agree, and I also agree that readers will differ in which books they find easiest to read. Different people learn in d

It is not obvious how to write a book. I agree, and I also agree that readers will differ in which books they find easiest to read. Different people learn in different ways. However, in some respects, it is obvious how not to write a book. Mathematics is not magically exempt from effective technical writing skills, nor all we have discovered about cognitive psychology and how people learn, nor anything else that goes into creating a generally good presentation.