Happy Birthday, David Crosby!

What we're watching here is a close, sometimes fractious friendship being patched up in public. The date is September 11 1970. CSNY's 4 Way Street tour ended in acrimony two months earlier but David Crosby had already invited Graham Nash and Neil Young to play on the sessions for his new solo album, and here Graham Nash invites David Crosby onto the hallowed BBC soundstage for what had been billed, in The Radio Times, as 'Graham Nash In Concert'.

It's a lovely show, defined from the start by Nash's plain, uncomplicated rendition of the modest, humble Simple Man, one of many stand-out tracks from his then-still-to-be-released May 1971 solo album, Songs For Beginners.

But today we’re here to honour the birthday of Mr David Crosby and look closely at an early unveiling of Traction In The Rain, a truly beautiful track from his 1971 masterpiece of stoned Lauren Canyon melancholy, If I Could Only Remember My Name.

Elsewhere in the broadcast Crosby is funny, abstract and laid-back. But have a look at this clip. When Graham puts in a request for his pal to “do something for me... sing Traction In The Rain?” he sounds like a nervous little Northern kid asking for his ball back, while Crosby is literally lost for words, and even takes a moment out to stare daggers at his pal, as if to say, “I wasn't QUITE ready to unveil this number just yet.”

The performance itself, however, is stunning. The song hovers in a strange place, somewhere between transcendental calm and the steel-eyed agitation you hear in that desperate final verse – “You know it’s hard for me to find a way / To get through another city day / Without thinking about / Getting out” – while Crosby's voice is about the best you’ll ever hear it: clear, dulcet, shimmering and lonesome.

Listen carefully and at the end you can just make out Graham Nash saying, “You were beautiful, man.”

He's not wrong. Round of applause. Happy birthday David Crosby.