Bob Dylan and Elvis Costello are touring together in America. This is information capable of sending a certain kind of music fan into rapture: two of our greatest lyricists on one stage.
When I joined a crowd of 20,000 at the Schottenstein arena in Columbus, Ohio, last week, it felt as if the geeks had inherited the earth. There were generations bonding over the mysterious pleasures of a well-turned phrase accompanied by well-tuned guitars, from ancient former hippies to hipsters just out of nappies.
In his dressing room, Costello admiringly pointed out that Dylan's legendary touring commitments mean he reaches places few stars ever visit, so his mere presence becomes an event. "It's not just whole families, sometimes the whole town comes out."
Yet clearly many of Dylan's fans feel an affinity for the complexities of Costello, who has come across a 30-year-old Alison on this tour (named after his 1977 classic) and a 19-year-old Veronika (named after his 1989 single).
Costello himself has 10-month-old twins with jazz singer Diane Krall, and joked about bringing them up as road babies. "We're onstage playing songs, and they're backstage, smoking cigars and betting on horses."
It is 30 years since Costello's debut album, My Aim is True, on Stiff, which has been repackaged in a deluxe edition. Although he never achieved the universality of Dylan, he was among the most influential songwriters of his generation, and remains a potent talent.
Vigorously accompanying himself on brash semi-acoustic guitar, Costello was a revelation. There was real musical and emotional breadth in a set shifting from ardour to anger to humour with a strong political undercurrent.
"River in Reverse," "(What's So Funny About) Peace, Love and Understanding?" and "Scarlet Tide" make eloquent points about America's unpopular administration.
You might expect an Englishman criticising a US president to get short shrift, but Costello was rewarded with repeated standing ovations. There is a sense that America's conscience is reawakening, and Dylan's audience embraced a performer drawing on the legacy of the original protest singer.
Yet Dylan's own protest days have long since passed, while his persona has become ever more inscrutable. In grey brimmed hat and sequinned cowboy suit, he spends the gig gently bobbing and jerking behind a keyboard, croaking lyrics as if to no one but himself.
He has a great band as usual, yet at the centre of the often mesmerising sound sits the star's incongruous keyboard, which has the old-fashioned, slightly comical tone of a theatre organ.
At times, it bogs down the fluid blues, then it will mysteriously develop the dubby atmospherics of a sinister fairground. Ballad of a Thin Man was an epic of scorn that still resonates with contemporary politics.
With songs such as "Working Man's Blues #2," there is little doubting where Dylan's sympathies lie, but then he is just as likely to play "Spirit on the Water" as a slice of pop schmaltz.
For a man of lyrical genius, he is not a great communicator: the only time he speaks is to introduce his band. With Costello, there is a sense of a great songwriter engaging with his audience, but Dylan forces you to take him on his own terms, or not at all. Given his iconic place in popular culture, it is simply enough for his audience to be in the same room.
Dylan has a catalogue that could deliver sets striking home on every level, but he prefers something more basic, playing rhythmic, groovy blues.
I am reminded of his early disavowal of poetic significance, when Dylan claimed in 1969 that he was "just a song-and-dance man". There is an almost mystical purity to this desire to boil his art down to entertainment basics, yet the songs are so immense, they overwhelm this simple format, sprawling out in every direction, taking on a life of their own.
The very fact that Dylan's performance is so odd and intentions so unfathomable helps keep us mesmerised.