The Apple II History site is hosting an updated version of the Apple II Redbook, long considered to be one of the most important manuals in the history of the Apple II Computer. This updated version has been reproduced and upgraded with additional materials included from Apple II history.
You can download the updated Redbook for the Apple II computer and get further information about the update from: https://www.apple2history.org/sdm_downloads/apple-ii-redbook-digital-edition-2023/
