Out of My Brain on the Train

"Unfortunately, the rock opera is also a bit of a cheat, as any classical music fan knows. If you're used to kicking back with a little Verdi, and someone comes along and plays you Pink Floyd's The Wall, declaiming, 'Behold! Here is another kind of opera to blow your mind,' you might point out that a rock opera isn't really an opera at all, but more, maybe, like a cantata, or a suite. Or even a musical, without the choreography. Rock operas aren't usually acted out, and you won't find much in the way of recitative. You get a cycle of songs, a main character, and, generally, a pretty trippy, gappy, plot. But on occasion, you can also get an album that numbers amongst rock's finest, one that is perfectly tailored to the sizable strengths of a singular band and a singular writer."

Colin Fleming at The Atlantic argues that the greatest rock opera is the Who's Quadrophenia.