Proofreading is the final quality-control step in the production of your book. Even the best of editors won’t pick up every single problem and error in your book, so proofreading is essential. It will be the difference between a professional-standard book and one that’s not quite there. One or two minor errors in your book aren’t the end of the world, but if you don’t have it proofread there could be much more than that, and this will reflect poorly on you and your business, which completely undermines everything you’re trying to achieve by publishing a book.
Editors and proofreaders can have particular things they like to change and other things they are happy to let go. (Editing can be as much art as science.) Something that one editor might not even register may be something that another always addresses, so combining an editor with a different proofreader means you cover more bases. Also, a proofreader reads the book in a different way, really focusing on line by line, word by word and letter by letter, not really concerning themselves with more ‘editorial’ areas. The proofreader will assume that the author and editor are happy with the content – their role is just to look for mistakes, nothing more.
An index is a valuable tool to help readers find what they want in your book, though I have noticed fewer and fewer authors are including an index in recent times. An index goes at the very back of your book, and lists all the major topics in your book in considerable detail.
Authors sometimes confuse an index with the contents page at the front of the book. The contents page lists the titles of the chapters and the page numbers, and sometimes the major headings in each chapter as well. The index goes at the back of the book and lists the major subjects covered and the relevant page numbers. It goes into much more detail than the contents list: a comprehensive index could have 500 entries while the contents page of the same book might have 15 entries.
Unfortunately the index created for your print book can’t be used as is for your ebook, because an ebook doesn’t have ‘pages’ as such so an index with page numbers isn’t much help. ‘Page 70’ on your tablet will be different from ‘page 70’ on your smartphone – if there is a page 70 at all, depending on the software being used to read the book.
You can have the print index re-formatted for your ebook. Creating an index for an ebook is a bit involved; it’s done with hyper-links, like a web page, so when you click on the link in the index you’re taken to the relevant page. An index is optional for an ebook because ebooks are searchable, so it’s actually not too hard for readers to find what they’re looking for.