During many interviews, U2 talked about how they initially planned "The Joshua Tree" as a double-album (under the title "The Two Americas").
But the band finally refuse to include some tracks, as it could be too complex to listen the "full" album.
Bono once said that the album is almost incomplete.
In fact, "With Or Without You" doesn't really make sense without "Walk To The Water" or "Luminous Times", and "Trip Through Your Wires" doesn't make that much sense without "Sweetest Thing".
In most of U2's history, B sides were either old reworked demos that had been sitting around for years, remixes or live tracks to attempt to capture the concert energy of U2.
In the case of "The Joshua Tree", 7 of the songs left were released as B sides of the first three singles. Island Records even marketed three-packs of these singles in many parts of the world as "The Missing Tracks"
To make your own "restored" Joshua Tree, you will need the album plus the first three singles.
You can also find the 2007 deluxe remaster that include the album with a second CD including those tracks.
Where The Streets Have No Name
Silver And Gold
I Still Haven't Found What I’m Looking For
With Or Without You
Walk To The Water
Bullet The Blue Sky
Running To Stand Still
Red Hill Mining Town
Race Against Time
In God's Country
Trip Through Your Wires
One Tree Hill
Deep In The Heart
Mothers Of The Disappeared