There is a 1915 edition of a book about Robert's Rules of Order *AND* a 1930-something book of lessons on it to learn, at archive.org.

• (As of 2022-09, one can search for "Robert's Rules of Order" then on the left-hand side click the filter for something like "always available", etc.)
• The 1915 version is "still in use" per https://robertsrules.org/versions.php .
• sources on ror