Ask someone who has taught a subject for a decade to write a course on it, and they will hand you a table of contents that mirrors the field: history first, then definitions, then the core theory, then applications, then edge cases. It is a perfectly accurate map of the subject.
It is also the order in which nobody has ever learned anything. A field is organised by what is true. A course has to be organised by what a beginner can do next. Those two orders almost never match, and choosing the wrong one is why most self-published courses and first-edition textbooks lose their readers by chapter three.
Topic order against capability order
Take an introductory photography course. Here is the same content arranged by the logic of the subject, and by the sequence of things a learner can actually do.
Topic order
- 1. A history of the photographic image
- 2. The physics of light and the sensor
- 3. The exposure triangle in full
- 4. Lens types and focal lengths
- 5. Composition theory
- 6. Post-processing workflows
By the end of week two the learner knows what a photon is and has not taken a photograph.
Capability order
- 1. Take a photograph that is correctly exposed
- 2. Control what is sharp and what is not
- 3. Decide where the subject sits in the frame
- 4. Shoot in bad light without the picture failing
- 5. Fix in editing what the camera could not do
- 6. Build a body of work that holds together
The physics arrives inside lesson one, in the two paragraphs where it is needed.
Nothing was cut. The theory is all still there, distributed to the moment where a learner has a reason to want it. That is the whole method, and it is harder than it sounds, because it requires you to remember being incompetent at something you are now expert in.
Write objectives with verbs you can watch
Every lesson needs one sentence describing what the learner will be able to do afterwards, and the verb in that sentence decides whether you can tell if it worked.
Unwatchable verbs: understand, appreciate, be familiar with, know about, be aware of.
Watchable verbs: calculate, distinguish between, build, rewrite, diagnose, choose, defend, predict, correct, summarise.
"The learner will understand database normalisation" cannot be checked by you or by them. "The learner will take an unnormalised table and produce a third-normal-form schema, and explain what breaks without it" can be checked in six minutes, and it also tells you exactly what exercise to write.
This is the point where a course outline stops being a wish list. If you cannot write a watchable objective for a chapter, that chapter is usually background that belongs somewhere else, or it is two chapters wearing one title.
What a single lesson contains
Repetition of shape is a feature here, not a failure of imagination. A learner who knows how a chapter is built spends their attention on the material instead of on navigation. Five parts, in this order.
The problem, before the solution
Open with the situation that makes this lesson necessary — something that fails, or is slow, or is ambiguous. A technique introduced before its problem is a solution in search of a reason to be remembered.
The explanation, once
Say it plainly and completely one time. Do not say it three ways in case the first fails; that reads as padding and teaches the learner to skim. If one explanation genuinely is not enough, the lesson is too big.
A worked example, fully
Every step shown, including the boring ones and the moment where a choice was made between two reasonable options. Skipped steps are where learners quietly conclude they are stupid and stop.
Their turn, at the same difficulty
An exercise that is genuinely the same problem with different numbers, not a harder variant. Confidence is built by success on the thing just demonstrated. Save the harder variant for the end of the set.
The failure modes
Two or three specific ways this goes wrong in practice, named. This is the part experienced teachers have and new authors forget, and it is the part readers underline.
Exercises are the book, not the appendix
Readers learn from what they do, which means the exercises deserve as much drafting time as the prose and usually get a tenth of it. Three rules keep a set useful.
Every exercise maps to one objective. If you cannot name which sentence in the lesson it tests, it is a puzzle you enjoyed inventing rather than an exercise.
Difficulty climbs inside the set, not between chapters. Start at the level of the worked example, end one step past it. A learner should finish the set slightly more capable than the chapter promised.
Answers exist, and they explain. A bare answer key tells a stuck learner they were wrong and nothing else. Two sentences of reasoning per answer turns the key into a second teacher.
The reliable test of a chapter is not whether it reads well. Hand it to one person who does not know the material, watch where they stop, and do not explain anything while they read. The place they stop is the sentence you assumed.
How much, and how long
Scope kills more instructional projects than difficulty does. Deciding the boundary early — in writing, as a sentence about who this is not for — is what lets the book finish.
8–15
lessons in a focused online course
12–20
chapters in a semester textbook
2–5k
words per chapter, exercises aside
The prerequisite question matters more than the length question. Write down exactly what the reader must already know, then check every chapter against that list. Most incomprehensible textbook passages are not badly written; they are correctly written for a reader two levels further along than the one the preface described. The general discipline of deciding shape before filling it in is covered in our piece on structure before detail, and it applies with more force here than in fiction.
A course differs from a trade nonfiction book in one respect that changes everything above: the reader is being assessed, formally or by themselves. Everything else — proposal, structure, evidence, revision — follows the pattern set out in how to write a nonfiction book.
Build the sequence, then fill it
Writer Atlas has an educational project type built for exactly this shape of work: a document tree where each lesson is a page you can drag into a new order when testing shows the sequence is wrong, search across every chapter to catch a term you defined twice, version history so a rewritten explanation is never lost, and export to DOCX, PDF or EPUB when the course is ready to go out.
Start writing freeQuestions about writing courses and textbooks
How long does it take to write a course?
For a subject you already teach, budget eight to fifteen hours per finished lesson including exercises and answer keys — so a twelve-lesson course is roughly a hundred and fifty hours, or three to six months at a realistic part-time pace. A full textbook in a field you know well is usually a one- to two-year project. Authors underestimate this because they price the explanation and forget the examples.
Do I need to be an expert to write instructional material?
You need to be reliably further along than your reader and honest about where that ends. Some of the best beginner material is written by people two years past beginner, because they still remember which step was confusing. What disqualifies you is not a missing credential but teaching something you have never actually done.
Should I write the course or record the videos first?
Write first, always. A script forces the sequence problem into the open while it is cheap to fix; a recorded lesson in the wrong order costs a reshoot. Many authors write the full text, teach it once to a small group, revise from where people stalled, and only then record.
How many exercises should a chapter have?
Five to twelve for a typical chapter, covering each objective at least twice. Fewer than five and a learner who misses one has no second chance at the idea; more than twelve and they stop doing them, which is worse than not having them. Mark two or three as essential so that a reader short on time knows which to attempt.
Can I self-publish a textbook?
Yes, and for professional and technical subjects it is now common. What you lose is institutional adoption — university course lists usually run through established publishers — and peer review. What you keep is rights, pricing, and the ability to release a corrected edition in a week rather than three years. Practical courses sell well independently; degree-track textbooks rarely do.
How do I keep a technical book from going out of date?
Separate the durable from the perishable while writing. Concepts, trade-offs and failure modes go in the main text; specific versions, interface screenshots and exact commands go into clearly marked boxes or an online companion you control. When the tool changes you update the boxes rather than rewriting chapters, and readers can see at a glance which parts are dated.