Chinese premier Zhou Enlai, when asked in 1971 what he thought the influence of the French revolution might be, replied sagely: "I think it's a little too early to tell." Whichever French revolution he was referring to, and there is some debate about that, his words have real relevance for anyone tackling a list of the top 100 albums of all time.
The "best" lists are made with the benefit of perspective. As it happens, it's now 50 years since the Beatles and the Rolling Stones changed the face of pop music with their first records.
For each of the decades since, music writers have laboured over this task of ranking the music that sound-tracked so many lives.
Now, Australian rock writers Toby Creswell and Craig Mathieson have taken their turn and come up with a book - The Best 100 Albums of All Time - based around a list that's fresh, controversial and weighted to give balance to 50 years of rock music.
Let's start with the controversy.
Sgt. Pepper doesn't even make the top 100. The Beatles aren't number one (Revolver is second). George Harrison gets an entry all on his own. There's a rap album in the top 10. For the first time ever there's a woman, Joni Mitchell, in the top 10.
It's noticeable that half the albums in the top 10 didn't sell many units when they were released but - and this is refreshing - Fleetwood Mac's Rumours makes a top-10 appearance, even though it sold like cheap beer at a cricket match on a hot day.
And while we're on the issue of popularity versus influence, there really is a controversial call in the list. The Monkees make it into spot number 56.
So, were there any fights between Creswell and his partner in crime while making up the list?
Creswell hesitates. "We've known each other pretty well for a long time. The big issue was which Bob Dylan album was going to be tops."
In the end, Highway 61 Revisited won the argument.
But why Dylan?
Again, there is a slight hesitation from Creswell, sensing he is moving close to an unexploded rock music land mine here. "Well, the Beatles did really blow it all up, creating a new type of music, but Dylan was a new art form. Dylan bought literature and pop music together."
Pausing ever so slightly again, he continues: "Before Bob Dylan, when you listen to the Beatles it is entertainment. After 1965 it changes."
In other words 1965 is rock's ground zero.
Having said that, Creswell and Mathieson did have some rules in making this list.
The first was the Beatles, Dylan and the Rolling Stones had to have limits on their contribution.
The second decision was that these writers didn’t try to conduct their own poll. They analysed all the polls and then researched the stories behind each album. In doing that they came up with some fascinating insights.
Frank Sinatra, who hated rock music and is possibly best known for his big hit singles like My Way, according to Creswell probably created the first "album". It was called In the Wee Small Hours of the Morning, a kind of heartbreak central for those who've lost in love.
Curiously, the album doesn't make the list but Miles Davis' Kind of Blue from 1959 does.
What's a jazz album doing in the rock domain? Well, that's the beauty of the book's approach, and it is the beauty of Kind of Blue, it simply defies categorisation.
And that leads us to another controversial decision - to put the Monkees' album Headquarters at number 56. As Pauline Hanson would say: Mr Creswell, please explain?
"The Monkees were manufactured and there was a strong criticism of them at the time. They weren't seen as authentic, but now we live in an age where authentic isn't even an issue. So in that way, because they had their own television show to promote their music they were very much a modern creation."
In other words, the Monkees in their Pre-Fabness were ahead of their time.
Of course there is one other question. Why make a list at all?
"Well," says the author, "it's important because it generates debate and it helps reframe what you think about this stuff, that has been part of our lives. It's also important because what we wanted to do was to make people look again and listen to music that they might not have listened to."
It certainly does that, and as Creswell points out perspective is everything and this is a list made in Australia, with no British or American bias.
There's one other thing reading the book does. The reader realises quickly that we probably won't be doing this in decades to come, for one very simple reason: the rock album may be dead.
"It’s possible," Creswell offers. "The CD ruined rock music albums because it made them too long."
It's worth remembering that what we call the album is based on the technology that created the 12-inch LP record. That blob of vinyl flattened out can only hold about 40 minutes of music before sound quality is lost. So each side was about 20 minutes.
As a consequence, artists began to make records with beginnings, middles and end within the confines of 40 minutes.
Creswell explains: "Layla by [Eric Clapton or] Derek and the Dominoes were two LPs devoted to unrequited love. It took you on a journey through that emotion, and bands don't do that anymore."
He laughs: "There are a few people like Arcade Fire that try to do it to keep the flame alive, no pun intended."
But even if CDs only contained 40 minutes of music, there would still be problems for rock LPs. Digital downloads mean people can simply buy a song, and increasingly, even if they pay for it, that's what they do. In other words, we're going back to the days pre Dylan and the Beatles, where singles ruled.
So are we really confronting the end of the rock LP?
I detect a real sadness in Creswell's voice as he says: "We may have seen the best of it."
Of course, a baby boomer would say that wouldn't they, I counter.
He laughs and then responds, again with a hint of nostalgia in his voice: "Well, they don't make films in the same way."
Which gets him on to another things that clearly disturbs him. "People these days don’t talk about what a song says anymore, they talk about the sound and how it relates to fashion or the video it’s associated with."
He collects his thoughts at this point before proceeding.
"I guess, you have to accept all art forms have a golden age, the novel isn’t what it used to be. Rock music came out of the '60s. There was a lot to write about, things have changed."
It occurs to me that Bob Dylan warned us about that, but it's a lesson we keep learning.