Typesetting is an extremely important part of the publishing process in both traditional publishing and self publishing. Typesetting focuses on the design of the inside of your book considering aspects such as typography, layout, margins, spacing etc.
If you're going down the traditional publishing route, this will be automatically included in the process of publishing your book. However if you're self publishing, typesetting is just as important and needs to be considered during your publishing process.
So, why is typesetting so important?
Impacts the reader's experience
Your book could be the best thing since sliced bread, but if its design makes it hard to read or it's full of design inconsistencies, readers may find it difficult to get into your story and give up. This may also lead to readers not reading your future books as the first one was poorly designed.
Compatible with different formats
When self publishing, you have the option to publish both eBooks and print books. Typesetting is extremely important for both formats, however eBooks open another possibilities of formatting, they are available on a range of different platforms and devices which means screen sizes etc will vary. A good typesetter will ensure that your work is anchored and won't be able to move about incorrectly when switching to different devices. It's also important to consider the differences in formatting an eBook and print book, such as page numbers and contents pages too.
Mistakes and Errors
Typesetting will ensure that your work is error and mistake free. By this, I don't mean spelling or grammar mistakes; your work should be 100% finished at this stage. A typesetter will be able to highlight and correct any errors such as words being split between pages or if a title or heading is in the wrong place.
Ensure consistency throughout
As I have always said, consistency is key throughout the whole editing process, but it's also essential in design too. Typesetting will ensure your fonts, font sizes, headings, spacing etc is all the same throughout your book.
And finally,
Making the right decisions
You have two options when it comes to typesetting; hiring a professional or doing it yourself. While a lot of self published authors have successfully typeset their own books, there is also the option of hiring one too. It's important to consider the benefits of hiring a professional typesetter such as getting professional and experienced advice on your book, learning what works best with readers such as font and size etc.
If you do decide to typeset your own work, make sure you do your research.