Most of what I do for a living is content editing, also called stylistic editing, line editing, and copyediting.

For more about the different levels of editing, see “Editing? What’s Editing?”

I go through each manuscript line by line, asking whether each sentence says what the author wanted it to say, and in the most effective way possible. (Good editors are at least a little bit psychic: usually we can figure out what the author was getting at even when the words get in the way.) Along the way I catch spelling mistakes, awkward punctuation, and usage gaffes, sure, but this is only part of the job.

In the last few months I’ve had two big proofreading gigs. When I’m proofreading, catching spelling mistakes, missing words, awkward punctuation, and dubious usage is what the job is about. You don’t have to be psychic to be a good proofreader. When you’re proofreading, the book is in proofs, meaning the pages look pretty much the way the reader will see them. The book has already been edited, and the editor was not you.

In other words, you want to change as little as possible.

For more about what proofreading is and isn’t, see “Proofreading 101.”

Proofreading generally pays a little less per hour than the editing I usually do, so why do I bother with it? I ask myself that whenever I accept a proofreading job. Here are some of my answers.

• When I’m editing, I often have to untangle snarly sentences. This can be exhausting. When I’m proofreading, someone else has done it for me.

• Proofreading demands that I focus on each and every word. When I’m editing, I often catch myself focusing on the sentences and overlooking the words that make them up. Proofreading reminds me that each word is important.

• When I’m proofreading, I’m following in another editor’s footsteps. Editors rarely get to see each other’s work. One of my recent proofreading jobs was a novel that included plenty of street slang and police shoptalk. Not only did I learn a few new words, I noted how author and editor had punctuated the kind of dialogue that isn’t covered in standard style guides. It gave me some ideas.

• Like many editors, I’m often tempted to meddle where meddling is not called for. Proofreaders must keep meddling to a minimum. I consider this a valuable spiritual practice.

• I get to proofread stuff that I wouldn’t be qualified to edit. A just-completed job was a multi-author essay collection dealing with the aftermath of the Arab Spring. I’ve edited a fair number of works, fiction and nonfiction, dealing with the Arab world, but this one included charts, tables, and lots of statistics. I’m in the “real life can’t be quantified” camp, but I don’t mind statistics too much when I’m proofreading.

That said, the next couple of months look like editing, editing, and more editing. Toward the end of November, I will definitely be ready for another proofread.