- May and June 2021: Extensive formatting of all units.
- 8/11/2020: Formatting done in units 12-18.
- 8/10/2020: Formatting done in unit 11
- 8/6/2020:
- About this Book and Author’s Note and Online Edition pages updated
- Extensive formatting done to improve visual appearance in units 1-10
- 8/5/2020: Print Textbook page title changed to Offline Textbook
- July 2020: Major edits, including corrections of typographical errors, were made throughout the text