I'm referring here to (math or other subjects) textbooks which include an exposition, main text and examples, references and exercises in each of the chapters.
From my experience, in most cases, it isn't feasible to really work through a chapter in a single reading. I keep finding myself getting tired (and confused) with the texts and jumping forward to see more complete examples and to try my hand at the exercises. And I keep wondering, why won't anyone make textbooks with more manageable chapters.
Why not cut the subject matter into small chapters, as in popular fiction, or as in Khan Academy tutorials? Is anyone here familiar with any research measuring the effect of chapter length on comprehension or any other parameters?