I like this blog post, it gives a succinct explanation, not just of the process a book goes through to be published, but it differentiates the different types of editing that editors do. It helps me understand how many different skills I need as a managing editor of a small magazine where I hold many different editing roles (although it doesn't cover all the managerial tasks I also do with the magazine).
Here's a summary of the list from the blog post (which is about book editors) and how it fits into my job:
Acquisitions editor: this editor is the entry point to the publisher for an author seeking to publish a book, though often in a big market like the US there is an agent between the author and the acquisitions editor. This editor may decline your "project" straight away or may present it to what the author of the post calls the "Pub board": the group that decides whether your project is viable (this is a business after all).
I am the acquisitions editor for Japan Harvest. I send out calls for proposals (we don't get many submitted otherwise, our pool of authors are missionaries and are very busy doing things other than writing). I receive proposals, summarise them, and usually pitch them to our executive editor and together we decide what we'll include and what we won't. I then communicate the terms with the author and receive their article at the due date.
Development editor: this editor does the first edit, but mostly writes their thoughts about the project and sends it back to the author for the author to revise. That includes things like improving the plot, dialogue, characters, structure, etc. Me or one other editor on my team does this, but not with every article. Quite a lot of articles we receive don't need the author to do major revisions. But of course we are dealing with much shorter pieces of writing (generally less than 1,300 words).
Substantive/line editor: this editor rearranges/deletes/adds paragraphs or sections, rephrases, reorganises, tightens, and recasts sentences or dialogue. They try to catch most spelling, punctuation, and grammatical mistakes, but it isn't their main focus. I do this too. If the article doesn't need a revision from the author, then we dive straight into this editing mode.
Copyeditor: this is the editor that most people think of when they think of editors. They are "persnickety" (to use the word the blog writer used). They pay attention to everything. Our editing process with the magazine means this task generally falls to a second editor after the first editor has done the above two steps. But our proofreader also doubles in this role (and often our designer sticks his or her oar in too).
Proofreader: this is the person who looks to catch all those last minute errors, after the text and graphics are in place in the digital draft of the magazine. We have a great proofreader, but after he's gone over the magazine, I also do a second complete read-through myself, and it's surprising how much I find at times.
Looking at this, I can see how at different stages I'm focused on different things. I shouldn't be so upset with myself for missing things in the early stages of editing, I'm not perfect and the itty bitty things that the proofreader picks up aren't my focus early on.
My editing role here is currently expanding, though not with the magazine. I'm now editing a blog that one of our Japan regions is publishing (see here). There's more coming as we revamp the OMF Japan website too and get more up-to-date stories flowing onto there.
It's good to take a step back for a moment and think about the different types of editing that are necessary, especially as I realise I'll need to get help. I think when people think about helping someone else with editing (in a non-professional fashion) they think about proofreading or perhaps copy editing. Not so many are experienced or willing to do development or substantive/line editing, though that's sometimes necessary.