“The road to hell is paved with works-in-progress.”
Copy-editing precedes proofreading in the process of publication: a text is copy-edited and then proofread for minor errors such as misplaced commas or overlooked spelling mistakes. The copy-editing stage is crucial, as it is here that style, content and presentation can be honed to perfection. The idea of the copy-editor as a reader's advocate and author's ambassador gives some sense of how important, and privileged, a role this can be - with attention to detail, a sound knowledge of grammar and punctuation and the ability to write clearly and concisely, a copy-editor acts as an intermediary between author and reader, making sure that the reader understands what the author has intended clearly and easily.
Proofreading, meanwhile, ensures excellent presentation and a chance to iron out any minor flaws in the text.