There are some ideas that are so simple and brilliant it's impossible to know exactly where and when they started. Who first placed the pickle on the hamburger? Who originally celebrated a goal by sliding on their knees? Who invented the air guitar? Who cares? Sometimes it's easier just to be thankful that such things exist in the first place.
So we won't spend too long here pondering which band was the first to play a concert at which they performed a classic album in sequence, in its entirety. The likes of The Who and Pink Floyd did it in the 1970s, of course, but those were concept albums, too new to count as "classics". Which means the trend may date back to 2000, when Brian Wilson was lured back to the world outside his sandbox to perform Pet Sounds around the world. Grown men wept, etc.
And if that wasn't where the "classic-album concert"was born, that was certainly the point at which acts realised that this was a novel way to add zip to the tedium of touring. Since then, the misleadingly named Don't Look Back series has made such concerts an annual event. Now, they're all at it. Echo and the Bunnymen play Ocean Rain! Primal Scream play Screamadelica! Lou Reed plays Berlin! And so on.
Ironically, this has happened at precisely the time people seem to have stopped listening to albums from start to finish, preferring instead to cherry-pick which songs to buy before distractedly shuffling them all into one another. Is the very idea of the album finished except in this new, live setting? We'll leave that to more serious writers to discuss.
Instead, let's celebrate the simple and brilliant idea of the classic-album concert while we can, because things seem to be reaching saturation point. A few years ago, Sparks played all 21 of their albums on consecutive nights in London. Last month, Steely Dan pulled off a similar trick in New York.
Suddenly, a seed of suspicion is planted: classic album given its due by artist and audience? Or public admission that this act will never be this good again?