What is Structural Editing?
In journalism it's called copy-editing—in other nonfiction and in fiction it's called structural editing. It includes proofing for spelling and punctuation, grammar and stylistic issues, continuity, formatting, and other matters of form that can shoot you in the foot during the writing, revision, and submission of your manuscript. A “book doctor” claims to be able to help you with plotting, characterization, imagery, and other ethereal elements of storytelling, but the value of such counsel is a completely subjective judgment; indeed, it might be totally worthless. Conversely, unless you've written a completely error-free manuscript, a good structural editor can always improve the nuts-'n-bolts of your work, something the “book doctor” can never promise.