For most books the honest answer is yes, you want both, because they do different jobs and neither replaces the other. But "both" is not a single purchase, and the order matters. This guide helps you decide what your manuscript actually needs and what can wait.
What each one does
An editor works on the manuscript itself. Depending on the type of edit, that means structure and story, the way sentences read, or grammar, consistency and facts. A proofreader checks a nearly final version for the small errors that remain: typos, stray punctuation, wrong words, and mistakes that appeared during layout.
The difference is distance. An editor changes the text. A proofreader should rarely need to, because the text is already settled.
Why one cannot do the other's job
Anyone who has read a book many times stops seeing what is on the page, and that includes the editor who just corrected it. Fresh eyes catch what the earlier readers have stopped noticing. That is why a proofread by a different person after editing and layout is worth having, even on a book that has been edited carefully.
A simple way to decide
Start from the state of your draft, not from a price list.
- You have a complete first draft and you are worried about plot, pacing or argument: start with a developmental edit or a manuscript assessment.
- The structure is settled and you want the prose clean and consistent: a copy edit, which often includes line-level improvements.
- The book is edited and laid out and you want a final safety net before publishing: a proofread.
- You are not sure where your book stands: a short sample edit will tell you what level of work it needs.
What you can sometimes skip
Not every book needs every stage. A short, well-revised book may not need a developmental edit. A very clean manuscript may need only a light copy edit before a proofread. A short nonfiction piece may combine the stages. The point is to choose on purpose, and to be honest with yourself and with the editor about the state of the draft. What is rarely wise is skipping the final proofread on a book you are about to publish, because errors in a finished book are hard to fix once readers have it.
Getting the order right
Whatever you buy, buy it in order: structure, then sentences, then layout, then the final proofread. Each stage assumes the one before is finished. If you are unsure which to start with, Marlowe offers a free sample edit of the first 1,000 words, and can assign a specialist for each stage when you are ready.