Say you send a 90,000-word thriller to a proofreader, and it comes back spotless. Every apostrophe is right, every stray double space is gone, and the invoice is paid.

Then the first agent who reads it tells you the murder happens far too late and the detective has no reason to care. The proofreader did the job perfectly. It was simply the wrong job at the wrong time.

Editing comes in three broad stages, and they work best in a particular order. Buying them out of order is one of the most expensive mistakes an author can make, so it's worth knowing what each one does.

Developmental editing looks at the whole book

A developmental edit (often called a structural edit in the UK) deals with the big picture. The editor reads the full manuscript and asks whether the story works: whether the plot holds together, whether the pacing drags, whether the characters behave like people and whether the ending pays off what the opening promised.

You usually get back a long editorial letter and notes in the margins rather than a heavily marked-up text. Those notes might suggest cutting a subplot, merging two minor characters, moving a reveal from chapter 20 to chapter 8 or starting the book three chapters later.

This stage is for a complete draft you've already revised at least once. It isn't the stage for polishing sentences, because many of them won't survive.

Copy-editing looks at the sentences

Once the structure is settled, a copy-editor works through the text line by line. They correct grammar, tidy clumsy phrasing, standardise spelling and hyphenation, and query anything that doesn't add up.

That last part matters more than people expect. A sharp copy-editor will notice that a character's eyes are grey in chapter 3 and blue in chapter 17, or that a village is ten miles from the city on one page and forty on another.

Many copy-editors also build a style sheet for your book, recording decisions such as "OK" versus "okay" or whether numbers are spelt out. It's useful later, for the proofreader and for any sequel.

Some editors offer a separate line edit, focused on voice and rhythm, which sits between the structural and copy stages. The same logic applies: it belongs after the structure is fixed.

Proofreading is the final check

Proofreading is the last pass before publication, ideally done on the typeset pages or the formatted ebook. The proofreader looks for whatever slipped through: typos, missing or doubled words, wrong page numbers, awkward line breaks and glitches introduced during layout.

A proofreader shouldn't be rewriting your sentences, and they certainly shouldn't be telling you the second act needs rethinking. If they find themselves doing either, the book reached them too early.

The expensive mistake of working backwards

The logic is simple once you see it: each stage assumes the previous one is finished.

If you pay for a proofread and a developmental edit then tells you to cut 15,000 words and rewrite the ending, every correction in those pages was wasted. The new chapters will also need copy-editing and proofreading from scratch.

The same thing happens on a smaller scale when authors skip straight to copy-editing because it feels more tangible. Clean sentences are satisfying to look at, but they don't rescue a book whose middle sags.

Most authors get the order wrong for an understandable reason. Structural problems are hard to see from inside your own draft, while typos jump off the page, so the typos feel like the real problem.

Working out where your draft actually is

Before you book anyone, be honest about the state of the manuscript. These questions help:

• Could you describe what your main character wants, and what stands in their way, in two sentences?
• Have you read the whole draft through in a few sittings since finishing it?
• Has anyone other than you read it from start to finish and told you where they got bored?
• Are you still planning to add, cut or move whole chapters?
• If a reader said the ending didn't work, would you be willing to rewrite it?

If you answered no to any of the first three, or yes to either of the last two, you're at the developmental stage. Don't book a proofreader yet.

If the structure feels settled, trusted readers have been through it and you'd only change things at the level of individual scenes, you're probably ready for a copy-edit. Proofreading comes after that, once the text is locked and laid out.

Getting more from a developmental edit

A developmental edit is usually the biggest investment in the process, so it pays to send the cleanest structural draft you can. Fix the problems you can find yourself, and the editor can spend their time on the ones you can't.

One way to do that is to run a manuscript analysis tool over the draft first. Software of this kind reads the whole book and flags things like timeline contradictions, characters whose details change and scenes that don't move the story forward.

It won't replace an editor's judgement, but it clears away the mechanical problems so your editor can focus on what the story needs.

Honest beta readers help in the same way: two or three people telling you where they lost interest can show whether you need a full structural edit or something lighter.

If you're still unsure which service to book, send a prospective editor your first chapter and a one-page synopsis, and ask them directly which stage they think the book is at. A good editor will tell you the truth, even when the honest answer means a smaller job for them.