Phil and Don Everly used to sing on their dad Ike's radio show when they were just kids. They were country through and through. When they started to make records, their rocking rhythm and incredible harmonies put them right in the heart of rock and roll's first wave.

They hit the scene just when big business first learned they could sell direct to teenagers. Much schlock and flim flam went out into the teen market in the mid 50s, but there was genuine treasure too.

The Everly Brothers succeeded, and their music has endured, because of their uncanny harmonies that embodied the idealised relationships of which they sang. And their songs were authentic expressions of what it was to be a teenager - in a time when nearly everybody got that wrong.

AUDIO: Listen to the story of the Everly Brothers

Charlie Watts was a young boy when he heard jazz drummer Chico Hamilton playing the brushes on a Gerry Mulligan Quartet record called Walking Shoes. Young Charlie knew, in that moment, that he wanted to be a jazz drummer too. Before long, he's drumming for the rock band he never left - The Rolling Stones.

It may seem counterintuitive, but Charlie's jazz roots made him exactly the right man for what would become the world's best live rock and roll band. His rock steady drumming anchored the Stones rhythm section, creating opportunities for Mick, Keith and soloists to shine.

And that would have been more than enough. But the best drummers do much more by doing less. They add fills and breaks - but no more than the song requires. Sometimes, Charlie would play a fraction behind the beat, creating a soulful, funky element that empowered Stones rock songs.

Charlie Watts was a great drummer, and a true gentleman.

AUDIO Listen to the story of Charlie Watts

We've been tracking the evolution of popular music, dropping in to the first year of each decade since the 40s. In 1961, the first wave of rock & roll was gone, seemingly without a trace. Many of its pioneers were still on the scene, doing smoother stuff. Teenage stars were popular that year, as were guitar instrumentals, particularly the surfing kind.

There were great songs on the airwaves in 1961. Real rock was rare, but it would make a huge comeback in the following years.

AUDIO Listen to the songs of 1961

The well known story of music in 1969 is the journey from the utopia of Woodstock to the murderous unravelling at Altamont. But there was another huge festival that year. Somehow it has slipped from our memories, our histories.
AUDIO Listen to the music of Summer of Soul

The Harlem Cultural Festival ran over six weekends in the summer of 1969, a remarkable celebration of black pride, black music. 300,000 people came to see the hottest acts, including Nina Simone, Mahalia Jackson, Stevie Wonder, B.B. King, Gladys Knight, Fifth Dimension and more.
 
Film of these concerts sat in a basement for 50 years. Now US music producer Questlove has made a feature film about the Festival, and why it vanished from our remembering of the 60s. Summer of Soul is an accomplished piece of story-telling, and the music is funk at its best.

In 1960s Texas, a band called Moving Sidewalks was a big deal, playing psychedelia to groovy people in Houston, opening shows for The Doors and Jimi Hendrix.

             AUDIO Listen to the story of Dusty Hill and ZZ Top

They became a hard-rocking blues band called ZZ Top, with Billy Gibbons, Frank Beard and Dusty Hill. They started having hits in the early 70s, and they saw the 1980s coming, hitching to the top on the brand new MTV.
 
ZZ Top has been playing ever since, and will continue, despite the death of bass player Dusty Hill in July.

At the tail end of the 1970s, we first heard Rickie Lee Jones, who had an Australian hit about some bloke called Chucky being in love. Turns out, the song was about Chuck E. Weiss, a famous fixture on the Los Angeles music and nightclub scene, contemporary of Rickie and Tom Waits. Together, they were night-hawks, making music and adventure under the California moonlight and neon glow.

Chuck started out as a drummer in Colorado, where he got to back blues legend Lightnin Hopkins. Chuck was a musician, song-writer, and he was the hippest of the hip for decades. He died in July - he was 76.

        AUDIO Listen to the story of Chuck E Weiss

We're observing how music changes decade by decade. We started in 1941 - ten years later, the big bands were largely gone, sweet singers were big, rhythm and blues was everywhere.
And we were on the cusp of rock and roll. A young Elvis Presley was listening to Big Boy Crudup songs on the radio. Bill Haley was singing with a western swing band - in 1951, he covered a record that some say was the first rock and roll song.
Listen to the sounds of 1951 here

Tom Jones is 81. An Elvis-like sex symbol in 60s Britain, and thus, easily lampooned. But Tom has one of the greatest singing voices ever. It's a force of nature. And he is a great interpreter of song. People who write songs dream of such a performer, someone who has the wisdom and talent to find and convey the very heart of their creations.

Listen to my thoughts on Tom Jones, and hear some of the great & lesser known songs in his extensive repertoire.

.My favourite thing about music is the way it's constantly changing. I find a style, a performer, I like and then it's a journey. I go with them wherever they might take me.

If you want to track the way music changes, pick a date, see what's playing, and then go forward, or back, about ten years. A decade is long enough to pick changes in styles, fads, and technology - all are big drivers of musical evolution.

So that's what I'm doing. I'm starting 80 years ago, in 1941. Big bands were playing war-time swing - singers were mostly one part of the act, rather than the stars.

The world was at war in 1941. Music was an important morale boost. Glen Miller, Memphis Minnie, The Inkspots,
Benny Goodman, Duke Ellington, Fats Waller - were the big stars of 1941.

Listen to the music of 1941 here

1971 was a great year for music. The rise of the singer-songwriter, the shift from singles to albums. There was so much good music released that year, and one of the best of 1971, of any year, was Blue - by Joni Mitchell.

A poet, visual artist, musical prodigy. Joni came from Saskatoon, the Paris of the Canadian prairies, to be at the epicentre of late 60s culture, in California's Laurel Canyon. Joni rose on the folk music boom that, by 1971,  contained, perhaps stifled her prodigious talents.

Joni left domestic bliss for  a fabled world journey and a late night flight. She hung out with James Taylor, writing songs as if her life depended on it Then, in a Hollywood recording studio, Joni brought them to life, in what remains one of the greatest ever musical acts of creation.

Blue is a miraculous record, full of the joyful sounds of a young woman accepting the challenges and burdens of her talents, honouring them, and going wherever they would take her.

Listen to my radio story on Joni Mitchell's Blue.