COME 10am tomorrow, thousands of Paul McCartney fans will be intent on getting their hands on a ticket for one of his December concerts in the UK. Given that he is, after all, one of the giants of contemporary music, and that he is only playing three gigs in Britain – Liverpool's Echo Arena, Glasgow's SSE Hydro and London's O2 Arena – it's safe to predict that demand will be high.

McCartney, 76, is one of a number of ageless, multimillionaire rock stars who still like to hit the road, now and then, simply because it's in their blood. Think of the Rolling Stones, Roger Waters, Paul Simon (now on his farewell tour), Neil Young, Bob Dylan, Van Morrison. Joan Baez is on a long farewell tour, Elton John is about to embark on his. And, at 85, Willie Nelson, will be playing gigs until he drops.

There is, though, a special excitement when McCartney announces a new album – Egypt Station, out in September – and an accompanying tour.

He and John Lennon, of course, changed the face of popular music in the 1960s. A measure of their creative relationship comes from Paul Simon. "You have no idea how competitive John Lennon was around Paul McCartney," he told his biographer, Robert Hilburn. "When I first met them, I felt like someone had taken all the oxygen out of the room. I almost couldn't breathe, they were so competitive, and that's what made them so great."

The Beatles story is well-known, of course – the initial encounters in the late 1950s, the dues paid in Liverpool's Cavern and in boisterous clubs on the Hamburg waterfront, the astonishing explosion of Beatlemania in Britain, the success of the debut album, Please Please Me, rush-released in March 1963 on the back of the chart success of the single of the same name.

Fifteen months after Britain, America latched onto the Fab Four, in January 1964 – "after which nothing was ever the same again," observes author Peter Doggett in his history-of-pop-music book, Electric Shock.

Classic songs poured out of Lennon and McCartney at a rate that still astonishes today. The band continued to reach creative peaks, especially from 1965 onwards when their restless experimentation in the studio led to such landmark albums as Revolver, Sgt. Pepper's Lonely Hearts Club Band, The Beatles (also known as the "White Album") and Abbey Road.

Doggett writes of McCartney embarking on a voyage of self-education, "immersing himself in ... the entire gamut of classical music, from plainsong to the avant-garde; electronic sound; jazz ... It was McCartney's ethos that was dominant during the second half of the 1960s, and sparked much of the music – from the Beatles and many others – that is remembered with such affection today."

McCartney began his post-Beatles career with a solo album, McCartney, in 1970. Egypt Station will be his seventeenth. He has also recorded and toured with Wings and released a number of classical records. There have even been ambient techno CDs.

His personal life has of course received considerable attention over the years, much of it relating to his marriages (to the late Linda Eastman, then Heather Mills, and Nancy Shevell). His wealth has been estimated at £820 million by the Rich List. In May he was made a Companion of Honour ("I think of how proud my Liverpool mum and dad would have been to see this," he said). He has long been outspoken on the issue of animal rights.

He recently guested on James Corden's Carpool Karaoke segment, cheerfully singing along to such McCartney classics as Let It Be and Penny Lane as Corden drove him around Liverpool. The video has recorded nearly 27 million views on YouTube.

Beatles expert and Glasgow journalist Ken McNab, who is working on a book about the band's final year, is in no doubt that McCartney is "rock'n'roll's Mozart". He adds: "Lennon was the driving force, and the heart and spirit of the band, but if it hadn't been for McCartney's relentless work ethic, the Beatles would never have lasted three years.

"Hamish Stuart, who toured with McCartney, once told me that music just pours out of McCartney. Every minute of every day, he'd be whistling a tune.

"Irrespective of what people think of his current output, even now he still does songs which are annoyingly catchy. You think his recent songs are no Hey Jude, no Let It Be, but they are so catchy. The fact is that he writes melodies that will live forever. I really think he is the greatest melodic composer since Mozart.

"People will still be singing Paul McCartney songs 200 years from now. A song like Let It Be – you have heard it so often and you think you know it. But the other day I was listening to it and the thought suddenly occurred to me that it is a work of absolute genius," he said.

"There are other great songwriters out there – Elton, Springsteen, and such legendary bands as Pink Floyd and Led Zeppelin – but McCartney's gift as a songwriter is unbelievable. And I say that more as a Lennon fan than a McCartney one.

"Stars like McCartney and Dylan are still working, still touring, because they just can't help it," McNab adds. "McCartney was at a party recently with Willie Nelson. They were discussing their careers and their future, and the subject of retirement came up, and Nelson said, 'Retire from what?' That's exactly right. McCartney has never thought of this as job. It's a hobby, and if he's happy to do it, and people still love him for it, then what's the issue?"