Amazon has just announced a new kindle format, Print Replica ebooks. Resembling PDFs, the new ebooks have fixed pages that preserve the page numbers and formatting of the original print edition. The font size is also fixed, but you can zoom in on a page and enlarge the text for comfortable reading, as well as pan across a page.
Although their pages are stationary, Print Replica ebooks will retain other Kindle features such as annotations, highlights, and the ability to sync your last page read across multiple Kindle applications. However, they can only be read with Kindle for PC and Kindle for Mac.
Kindle Print Replica ebooks can be rented for a period between 30 and 360 days, so expect to start seeing more and more textbooks produced in this format.
You can find more information about Kindle Print Replica Content on Amazon.