Important Notes: The e-book is fine to use; make sure it is Volume 2, 2022 -- it has a blue cover. You only need Volume 2, which covers our time period. The 2022 edition is needed as there are substantive changes from earlier editions. For used copies, be sure that you get Volume 2 (not volume 1 and not the edition that combines both volumes 1 and 2 into one book, as this is twice as expensive).