Beatle producer, the late George Martin, once said that he always viewed The Beatles' Abbey Road as the natural successor to Sgt Pepper’s Lonely Hearts Club Band. It’s the idea of a suite of songs (which was central to that album, recorded in 1967) building up to form a whole. Martin said that was what he was after with Abbey Road too - and that Paul McCartney was with him on this as a concept much more than John Lennon ever was.

And that’s probably the reason Abbey Road ended up being an album essentially in two parts.

On vinyl LP, Side One is very obviously made up of individual songs, put together in the traditional sense. It’s much more a pure rock-influenced approach (which is what Lennon wanted).

Flip the album over however and Side Two is more a band thinking in Sgt Pepper symphonic terms (an approach that McCartney backed, and the one which George Martin preferred).

On Side Two the songs all segue into each other. It’s one long medley really, a continuously moving piece of music. Martin again: “They could even be fragments of unfinished songs - they didn't need to be long. We said let's just run them all together”. And so that’s what they did, and that's why Side One stands out as being so different to Side Two.

The other element linking Abbey Road to Sgt Pepper is that their sound engineer, Geoff Emerick returned to the fold to assist George Martin in the control room. Emerick had decided he’d had enough of the Beatle bickering and infighting during the White Album sessions, and had quit. But now he too had returned to inject some of his technical magic into proceedings. In a very real way the old team was back together.

Despite being released before Let It Be, Abbey Road was actually recorded after that album. The recording sessions took place mainly in July and August, 1969. After the fractured and demoralizing experience of the Let It Be sessions (which despite being present, George Martin felt he did not produce), Abbey Road was an attempt at a return to form - working in the studio intently together on a project the way they used to make albums. And what a glorious end to their career it formed.

The album kicks off with Lennon’s “Come Together”, a bluesy, rocky, funky tune that is one of his very best. It’s a song that is not without controversy though as Lennon, just like his band mate George Harrison would experience the following year with his song “My Sweet Lord”, was sued for breach of copyright. The copyright holder of the Chuck Berry song “You Can’t Catch Me” said it was similar in sound, and in its lyrics. The case was eventually settled in 1973, with Lennon agreeing to record some old rock’n’roll covers also controlled by the same owner. These eventually became part of his solo Rock’n’Roll LP, released in 1975.

“Come Together” is immediately followed by one of George Harrison’s very best songs. “Something” is regarded as one of the great love songs and has been covered too many times and by too many artists to list here. It became George’s first Beatle A-side when the first single was released from the Abbey Road album. It is George clearly demonstrating he could write top-shelf songs, perhaps not with the same frequency of John and Paul, but songs that are certainly their equal.

The next track, “Maxwell’s Silver Hammer” (and to an extent “Octopus’s Garden” too, which closely follows) is The Beatles flicking the switch to vaudeville, as they could do so easily. Both are novelty tunes, a bit of fun.

“Oh! Darling”, also on Side One, is Paul’s tribute to the 1950’s, and a great example of his amazing vocal range. He worked really hard on it over a number of days to get the vocal sound he heard in his head just right. A definitive McCartney vocal if ever there was one.

The closing song on this side is another absolute Lennon classic. “I Want You (She’s So Heavy)” is a bluesy, broody and intense love song to Yoko Ono that is tough and urgent. As we’ve written elsewhere, this song is simple and breaks a lot the usual songwriting rules as it builds and builds to a point - and then it abruptly cuts out. It is another Beatle innovation dramatically ending what would have been (in the vinyl days) Side One of the LP.

If you could have any song to be the oh-so important opening track on Side Two of a Beatle album, you could do a lot worse than have George Harrison’s “Here Comes the Sun”. What a classic with which to begin the musical journey that takes us to the closing tracks “The End” and “Her Majesty”.

“Here Comes the Sun” then morphs into the beautiful “Because”, which leads to “You Never Give Me You Money”, a Paul McCartney song which is reflective of the long meetings The Beatles were obliged to have as part of the huge business empire they were trying to run at the same time as being its principle creatives.

These songs all form the beginnings of what becomes a lengthy song montage including “Sun King”, “Mean Mr Mustard”, “Polythene Pam”, “She Came in Through the Bathroom Window” (which might be based on a true story about young Beatle fans breaking into Paul’s London home in St Johns Wood), and which reaches its zenith at “Golden Slumbers". It's inspired by a words from a very old lullaby dating back to 1603 which Paul McCartney accidentally discovered in a piano lesson book and which was given a beautiful orchestral arrangement, written by George Martin.

The album then careens into “Carry That Weight”, another song about The Beatles’ financial difficulties at the time - again containing strong Beatle-esque orchestral motifs supplied by George Martin. It all then magically becomes “The End”, beginning with a Ringo Starr drum solo (the was first of his recording career – and which he needed to be persuaded to do), then an individual guitar section where each Beatle (except Ringo) takes a lead guitar solo, one after the other. First is McCartney, then Harrison, then Lennon. Then they repeat.

This is followed by 17 seconds of silence which makes you think the album has come to close. But it hasn’t. Quite accidentally a little snippet of a song called “Her Majesty” (all 23 seconds of it) was left on the mastering tape by an EMI engineer. The Beatles liked this little “Easter Egg” of a song that just randomly appears as the very last Beatle tune to be released (at the time) and so they decided to keep it there. Another Beatle first.

Now to the famous cover. Surely the term “imitation is the sincerest form of flattery” comes into play here as it is an often-copied image. The idea was simple enough, and may have come from Ringo Starr. He suggested that instead of going somewhere exotic for the cover photo shoot, why not just do it right outside the EMI studios in which they were working? Paul sketched out a rough idea and photographer Iain Macmillan was hired. He erected a step-ladder in the middle of busy Abbey Road in London while a policeman temporarily stopped the traffic. Macmillan had the four Beatles stride across the nearby pedestrian crossing. He had about ten minutes to take his iconic shot. It's now one of the few pedestrian crossings in the world to have its own website and webcam, in operation 24/7. (The crossing is actually a few yards further down the road than it used to be, but that hasn’t stopped fans from all over the world visiting to have their photos taken, again stopping traffic on that familiar zebra crossing).

Abbey Road was issued in the UK on September 26, 1969 and in the US on October 1, 1969.