What does a proofreader do?

We all make mistakes. A slipped finger creates a typo, tired eyes miss a paragraph that should be somewhere else, or an interruption causes you to reverse two numbers. But here's the trap: When we check for mistakes ourselves, we know what we meant to say and our brain tricks us into thinking that that's exactly what we put down, often making us miss crucial errors until it's too late. This is where I come in. As a proofreader, I do the following:

* Correct spelling, grammar, and punctuation
* Ensure consistency of style
* Watch for omitted or duplicated text
* Make certain that the text conforms to the format and eliminate any confusing word, column, or page breaks
* Check page numbers and page headings for mechanical, grammatical or placement errors
* Match the table of contents against chapter titles, front matter, page numbers, appendices, indices, etc.
* Ensure that illustrations, captions, and labels correspond with each other and with the text.
* Check or insert cross-references where appropriate.
* Advise on any language which might be misconstrued.