The history of rock music really starts with the end of WWII and the resulting 'baby boom' which created a greater number of teenagers in the 1960s.

The musical roots of 1960s rock music are wide-ranging, starting as far back as the big swing bands of the pre-war era (such as Glenn Miller and Count Basie) that the 1960s teenagers' parents listened to as youngsters. There were also the smaller 'rhythm combo' groups, usually of only 4 or 5 players, whose tunes were popular on the jukeboxes of the day. Then there was country and western - especially what was called 'Texas Swing', of which Bob Wills & the Texas Playboys were the most famous. In Memphis, Sam Phillips and his Sun Studios created rockabilly, with stars such as Elvis Presley, Jerry Lee Lewis, Carl Perkins, Johnny Cash and Roy Orbison.

Blues was a key source and influence on rock music, especially as it evolved from acoustic solo guitar music in the South to the electric guitar, bass and drums combos of Chicago blues, with artists such as Muddy Waters, B.B. King and Howlin' Wolf. And the invention of the electric guitar itself cannot be underestimated.

At the beginning of the 1960s, the rockabilly stars of the previous decade (such as the Everly Brothers, Elvis Presley and Roy Orbison) were still having hits but the older pop music artists were finding it difficult to stay in touch with the younger generation. Pop became a youth phenomenon.

There were 4 main pockets of early 1960s popular music: the East Coast doowop and girl groups, the black R&B and soul scene (notably as produced by Atlantic and Motown), country music (centred on Nashville) and the Southern California scene.

The Southern California scene was first dominated by instrumental surf groups such as the Surfaris and Dick Dale & the Del-tones, who helped define the rock guitar sound, and then the Beach Boys added vocal harmonies. But the key advances were happening in the studio.

With 1963, rock'n'roll started to evolve into rock music. An important element was the so-called 'British Invasion' - in particular the 'Mersey-beat' of the Beatles and Gerry & the Pacemakers. Britain had had a poor music scene in the early 1960s, with most rockers imitating Elvis Presley. But the blues clubs had gradually been building on their Chicago roots to create something new and fresh, from which emerged bands such as the Rolling Stones, the Yardbirds and the Animals. Liverpool did not have a great underground scene but had a more commercial brand of rock bands as a result of the efforts of producers such as George Martin. The two styles complemented each other and created rock music. The most influential of the second generation of British rock bands were the Kinks and the Who. Cream and Led Zeppelin built on this tradition and played loud blues-based or 'heavy' or 'hard' rock.

Meanwhile the arrival of the Beatles in the USA in 1964 and their performances on the Ed Sullivan Show had a massive impact. Their sound and attitudes influenced everything that came afterwards and killed off almost all of the existing American groups, with the exception of the Beach Boys, the Four Seasons and the leading Motown acts. In their place appeared new groups that looked and sounded just like the British groups, including the Beau Brummels, the Buckinghams, the Sir Douglas Quintet and the Turtles.

Then folk music went electric, most notably with Dylan's performance at the Newport Folk Festival in 1965. And the Byrds had their first big hit with Dylan's Mr. Tambourine Man, largely based on a Beatles sound.

The next 2 years, from 1965 to 1967, saw the most amazing experiments and changes in rock music ever. The Beatles and  Beach Boys continued to compete and the music of each became more obviously influenced by drugs. Sgt. Pepper became the anthem for 1967's Summer of Love; it was the height of flower power, arty progressive music that seemed to influence the social fabric. San Francisco was the centre for acid rock and psychedelia, with bands such as the Grateful Dead and Jefferson Airplane, while Los Angeles had the Byrds, Love and the Doors. The boom in rock music also helped to resurrect the blues, with Jimi Hendrix and Janis Joplin plus other bands such as the Band, Creedence Clearwater Revival and the Doobie Brothers revisiting traditional white and black music. In the south this revival movement later led to Southern rock with the likes of the Allman Brothers.

This all came together in the Monterey Pop Festival, which featured many leading bands of the period including the Byrds, Jefferson Airplane, the Grateful Dead, the Who, Jimi Hendrix, Moby Grape, Big Brother & the Holding Company (with Janis Joplin) and Country Joe & the Fish.

But this all began to change in 1968. In that year both Robert Kennedy and Martin Luther King were assassinated. America's escalating involvement in the Vietnam conflict led to widespread student riots, the civil rights movement gave up its nonviolence philosophy and in Oakland the Black Panther movement was born. Rock music took a step back from drug-fuelled experimentation and turned more to protest, notably with the Velvet Underground in New York and the Fugs in San Francisco. And the rise of the Black Power movement helped spur soul music to heights of popularity never before experienced, with Otis Redding and Aretha Franklin becoming major stars.

1969 saw two important rock festivals - Woodstock in August and Altamont in December. While people tend to remember Woodstock fondly, in retrospect its overwhelmed facilities (with 450,000 rather than the 200,000 expected) and lousy weather were possibly an indication that it was really the end of an era. Then violence at Altamont culminated in a member of the audience being stabbed to death as the Rolling Stones performed on stage. And this was shortly followed by the Charles Manson murders.

By the end of 1969, Joplin, Brian Jones and Jimi Hendrix had all died of drug overdoses. A year later, the Beatles broke up and Diana Ross left the Supremes. One year after that, Berry Gordy moved his Motown operations from Detroit to Los Angeles. The musical decade of the 1960s was over.

Meanwhile, in Britain, rock music took on more of an underground or experiemental feel, growing out of the psychedelic clubs of London and Canterbury with bands such as the Soft Machine. Progressive music developed into convoluted and extended arrangements with bands such as Traffic, Family, Roxy Music and Yes. Folk rock and progressive folk were developed by the Pentangle, Fairport Convention and the Incredible String Band.

In the USA, the excesses of the 1960s were replaced by a more peaceful style, with the emergence of country rock as performed by the later Byrds, Flying Burrito Brothers and the Eagles.

In Germany, bands such as Kraftwerk, Tangerine Dream, Can and Faust laid the foundations for popular electronic music.

The most important rock development in the later 1970s was the emergence of punk rock. Some bands such as Talking Heads managed to combine the energy and aggression of punk with the depth of rock and the rhythms of dance music.

By the 1980s, rock had diversified so widely that it was no longer meaningful as a single genre.