Instruction Manual

The Instruction Manuals are booklets packaged in with the Games. All of them contain a backstory to the game in addition to control usage and in-game menu navigation. The older titles' booklets are valued among collectors, as gamers often threw away the box and manual.

The Legend of Zelda
The initial title's manual has been one of the most detailed to date. This may have been to make up for the lack of in-game text. Every dungeon, Boss, Item, and Enemy was named and included artwork of each.

Zelda II: The Adventure of Link
This manual also contained more backstory than the actual game. However the manual did not name all of the Palaces as the actual game did.

Canon Considerations
Typically Legend of Zelda series fans claim in-game content to be of higher canonicity than manuals. One consideration to bear in mind with the older titles is the data limits of the cartridges compared to the lack of limits of print. Case in point A Link to the Past's representation of Link's hair color. Which appeared pink in-game but the usual blonde in the artwork of the game's manual.

Manuals of Ported Games
Thus far, the manuals of older games ported to newer systems has had significantly less content than the original versions. Canon purists often place the newer version higher than the older version. Nintendo's reasoning may have simply been one of costs instead.