I don't know how many chapters my books had but I had one (how-to for staff on using moodle 2.5 and all the weird stuff we'd added) that when printed was over 400 pages. They included links and, at times, video and images. Book is awesome!
There are different kinds of books are available online where students can do online study and get the best study options.I have checked about the https://fintechzoom.com/fintech_news_highlights/how-the-covid-crisis-impacts-the-financing-education-sector-in-the-usa/ options where education sector is also got affected due to covid crisis which makes it difficult for the students to read the books.