Commercial publishers do an excellent job of producing a professional product but many people are unaware of the serious limitations. You are locked in with a commercial publisher, whereas if you self publish you are in complete control
"The author is responsible and in control of entire process including, in the case of a book, the design of the cover and interior, formats, price, distribution, marketing and public relations. The authors can do it all themselves or outsource all or part of the process to companies that offer these services"
Newsletter (e.g. MailChimp) for marketing to target audience
You may need to set up a business entity
Create a web site to market, sell and provide downloads
You need an ecosystem for your book, to include social media (Facebook, Twitter
We set up a sole proprietorship which was very simple, not requiring a lawyer. We are able to deduct many book-related expenses and expenses as a "consultant"
Make your textbook multilingual. Have overseas university translate content. Translation software?
This will not pertain to every author but keep in mind that many foreign academicians speak English so be sure you do everything possible to support an international audience
Scribus: free for Windows, Mac and Linux. Steep learning curve
Lucid Press: low cost, web based with multiple features. Free for faculty/students
Scrivener: 45$ for Windows and Mac. Export to EPUB and .mobi
Mac Pages is working out better than Microsoft Word for a new chapter I am working on. If I had it to do over again, I would probably format in Lucid Press, in order to lock down images