Along with Speakers, Flipper's, Beatniks, Ampex and Streaks, The Silver Thunders were responsible for one of the most exciting chapters of the early rock years in Bogotá, Colombia.

Eccentric and volcanic, the quartet recorded an album in 1968 which wasn't released at the time.

Rescued from old cassette tapes, that recording finally comes out five decades later, displaying the rebel spirit of a group influenced by Mersey beat, surf and garage.

"Me gritan melenudo" contains 'Alma agobiada', their only original composition, plus raw covers of The Beatles, The Monkees, The Troggs, Lovin' Spoonful, Miriam Makeba and The Ventures.

It also includes two more Beatles songs and a couple of covers from the Wild In The Street soundtrack recorded in 1970 by Los Yoguis, as the group was known at the end of their short-lived career.

Plus many photos, a family tree and the detailed story of the band. More details? In 1968, The Silver Thunders enjoyed a good reputation within the Bogotá rock circuit.

Whether it was for the crazy and insolent image they projected or for the flair they exuded on stage, the four young musicians were regulars on radio and television programs, at youth dances and legendary discos like La Fiebre, The Ship, La Caverna, La Jaula, La Bomba, Panauto and El Diábolo de Oro.

All they needed was a record to consolidate their popularity. Today, none of the three living members of the band remembers where they got the money from to invest in the recording, but they got together three or four hours a week over several months in 1968 at the studio Suramericana de Grabaciones.

The details of the sessions are hazy and nobody knows who sat behind the mixing desk. However, Jorge López (lead guitar) and Orlando Córdoba (bass guitar) both say that the studio was uncomfortable and precarious.

This didn't undermine the group's upbeat spirit. That's how things were back then: no editing tricks and no option of doing several takes, as reels of tape were very expensive.

The Silver Thunders, with Edgardo Córdoba (rhythm guitar) and Carlos Cardona (drums) completing the line-up, recorded live a repertoire influenced by Mersey beat and British R&B, American surf and garage, the psychedelia of The Beatles and a dash of African pop.

This is conveyed in the raw cover versions of 'And Your Bird Can Sing', 'Got To Get You Into My Life' and 'A Day In The Life' by the Liverpool four; 'Mary, Mary' by The Monkees; 'Wild Thing' by The Troggs; 'Wild Angels', taken from the soundtrack of the film of the same name; 'Summer In The City' by The Lovin' Spoonful, plus a surprising cover of 'Pata Pata' by the South African artist Miriam Makeba.

Although the presence of The Beatles predominates, the band delves deep into style of The Ventures in 'Good Thing' and an exquisite and naive cover version of 'Strawberry Fields Forever' after the instrumental track that Don Wilson and Bob Bogle's combo made famous in 1967.

The recording also includes 'Alma agobiada', an original song by Carlos "Caniche" Cardona and the only remaining example of The Silver Thunders' own repertoire.

At the end of this unprecedented adventure in the studio, they cut an acetate disc and were handed a tape that contained the recording.

Armed with this material, they went to knock on doors of the Bogotá record labels. The response was a resounding no.

Some rejected it saying the quality of the recording wasn't good enough and others said that the beat sound was no longer in fashion.

A couple of years later, Jorge López went off to finish his studies and Carlos Cardona joined the ranks of Los Flippers.

The Córdoba twins carried on playing, accompanied by Hernando Orjuela on keyboards and Eduardo Acevedo on drums.

They fell under the influence of the mysticism of the guru Maharishi Mahesh Yogui. At the end of the decade, the four Silver Thunders became Los Yoguis and recorded 'Birthday' and 'Revolution' by The Beatles at the Ingeson studios, as well as 'Shape Of Things To Come' and 'Listen To The Music', both from the soundtrack of the film Wild In The Streets.

The tape with the two recordings remained at the Córdoba brothers' house for many years.

Oscar, another brother, had the good sense to digitalize it before it disappeared in a future house move.

There was a cassette that was used in the mid-90s to launch a promotional release sponsored by Plutarco García Herreros, a nostalgic doctor who produced a hundred copies and shared them among band members and the guests at an alumni party at the Faculty of Medicine of the National University of Colombia.

This cassette is now a cult object. A couple of copies survive, and it has ended up serving as the master tape so that 50 years later, the enthusiastic, naive and savage sound of The Silver Thunders returns to its elemental destination: the shiny grooves of a vinyl record.

- Luis Daniel Vega