THE FIRST ENCYCLOPEDIA OF POP IN 26 WEEKLY PARTS, UK. This series accompanied the broadcast by the BBC of a history of popular music: there were 26 one-hour parts of 'The Story of Pop', transmitted weekly on Saturdays, from 29 September 1973 till 23 March 1974.
The magazines covered aspects of pop and rock from the early origins, through the rock and roll explosion of the 1950s, Merseybeat and psychedelia in the 60s through to glam rock in the 70s, in a roughly chronological order, all with lots of photos and illustrations.
The magazine was originally intended to be of 40 issues, but due to popularity it was extended with a further 13 ‘Special Volume’ magazines also issued.
Phoebius Publishing, London. A French version called HISTOIRE DU ROCK was published in Canada (Quebec).
Thank you to Eric Galzi for the images and information.