Obviously "The Joshua Tree" was U2's breakthrough album, but in retrospect I would make a case for "War" being their most pivotal work.  In a word, this is the point where the lyrics catch up with the music.  You can listen to "Boy" and "October" and find the sound, which in the beginning was focused on the Edge's jagged guitar riffs ("I Will Follow" is the best song from those two albums), but the lyrics are pretty much just something for Bono to do while the band plays on.
However, when we get to "War," things have clearly changed.  If the title and the cover shot (a young boy, his lower lip bloodied, his hands locked behind his head a standard pose of submission), then the lyrics of "Sunday Bloody Sunday" quickly settle the matter.  Along with "New Year's Day" and "'40'" they place "the Troubles" at the heart of the album's gestalt.  The political position they are taking vis-a-vis the sectarian strife in Northern Island is rather nebulous, but there is a potency to the music and the lyrics hitherto unfelt in U2's songs (forever captured in the music video of the group performing the song at Red Rocks).  But then there is nothing wrong with offering awareness and concern rather than solutions.  This is a problem that has been boiling over for centuries.
When an artist or group makes it big, there is a tendency among their true fans (defined as those who were in on the action before the bandwagon loaded up), to look back at one of their "early" albums with great nostaglic affection.  For U2 that album would have to be "War."
Obviously "The Joshua Tree" was U2's breakthrough album, but in retrospect I would make a case for "War" being their most pivotal work. In a word, this is the point where the lyrics catch up with the music. You can listen to "Boy" and "October" and find the sound, which in the beginning was focused on the Edge's jagged guitar riffs ("I Will Follow" is the best song from those two albums), but the lyrics are pretty much just something for Bono to do while the band plays on. However, when we get to "War," things have clearly changed. If the title and the cover shot (a young boy, his lower lip bloodied, his hands locked behind his head a standard pose of submission), then the lyrics of "Sunday Bloody Sunday" quickly settle the matter. Along with "New Year's Day" and "'40'" they place "the Troubles" at the heart of the album's gestalt. The political position they are taking vis-a-vis the sectarian strife in Northern Island is rather nebulous, but there is a potency to the music and the lyrics hitherto unfelt in U2's songs (forever captured in the music video of the group performing the song at Red Rocks). But then there is nothing wrong with offering awareness and concern rather than solutions. This is a problem that has been boiling over for centuries. When an artist or group makes it big, there is a tendency among their true fans (defined as those who were in on the action before the bandwagon loaded up), to look back at one of their "early" albums with great nostaglic affection. For U2 that album would have to be "War. "