In fact, you can hear Flea, bass player for the Red Hot Chili Peppers, confirm his belief that U2's guitarist really does have the funk on 'Close to the Edge'. In a heart-warming exchange, Flea talks about his roots, and of finding 'the divine voice' through music.

Someone else who knows his funk from his punk - will.i.am - tells Edge how musical creativity informs everything he does (from designing 'smart masks' to broadcasting from the surface of Mars). "I took a lot of my cues from U2 and all you stand for," he confesses. "Open hearts to open minds."

Elsewhere, Bono and Adam re-unite with Chris Blackwell, founder of Island Records. Chris came to see U2 for the first time (as Bono recalls) on a cold winter's night, at a London pub, in flip flops. "There was no doubt in my mind you'd be successful," he assures Bono, who wonders, looking back, what the unsigned young band from Dublin was really like that night at the Half Moon, Herne Hill …

DJ John Kelly, meanwhile, has been mining a rich vein of poetry in his Elevation show. He talks to Peter Hale and Jesse Goodman about Allen Ginsberg (and their tribute album to the beat poet, featuring musicians such as Gavin Friday).

John also talks to Joy Harjo, the US poet laureate (and the first Native American to hold that post). In a world that's so divided, she says "the only meeting place can be in art".

And on a similar note, the poet Padraig O'Tuama chats with John and Edge about reconciliation and peace. Padraig's 'a believer in the human spirit', says Edge. He has a fine way with words, too.

Talking of which, it was Bob Dylan's 80th birthday in May, and Bono wrote something - an epic? a poem? a four-minute toast? - for the man he calls "the Alchemist" …

"Give it up, give it up, come raise your cup 
To the boy with the golden fist.
The golden glove, he'll beat hate into love,
Raise your glass to the Alchemist."

You can hear Bono's whole tribute, and more highlights beside - including guest DJs Jeremy Piven on Sunday Bloody Sunday, and Jenny Huston on There is a Light - all in episode 5 of Xtracts, out now!

…

You can also check out Chris Rock, David Byrne, Phoebe Robinson & Bryan Stevenson on Episode 1 of U2 X-Radio’s XTRACTS.

Adam hosted Episode 2, an ‘All That You Can’t Leave Behind’ Special.

The bumper end of year edition featured - amongst many others - Guy Garvey, Kevin Godley, St Vincent, Howie B… and Bono Calling a very special guest, Ava Du Vernay.

And Episode 4 includes Daniel Lanois, Kate Raworth, Bono reading a psalm and Adam reading William Blake.