How do I get iTunes to play all music from a specific year?
Use a Smart Playlist. These are playlists that are dynamic and can be built off filters on track metadata.

To create a new Smart Playlist select File &gt; New &gt; Smart Playlist... (or Opt-Cmd-N) and then set the following options to build a Smart Playlist that always contains all the tracks that are from 1969 in your library:



If you wanted to limit it to a specific genre from 1696 press the + button to add another filter criteria and pick a genre like so:



You can filter in all kinds of ways -- Smart Playlists are incredibly powerful.