The Beatles Middle Period
The long and storied musical career of the Beatles - one that ultimately saw the release of hundreds of songs over the span of some eight years - is often broken down in three distinct parts: The Early Period, the Middle Period, and the Late Period. Any one of these periods, taken individually, would have been more than sufficient to guarantee The Beatles a place in music history. Taken together, they're testimony to levels of creativity that no other artist had ever achieved before... or likely ever will again.
The Beatles Middle period is most closely associated with the albums Rubber Soul, Revolver, Sgt. Pepper's Lonely Hearts Club Band, Magical Mystery Tour, and Yellow Submarine and the iconic singles Strawberry Fields Forever and Penny Lane. Yet the period can be be traced as far back as Day Tripper and We Can Work It Out, recorded in October of 1965. Though the beginning of "the middle period" has no clear line of demarcation, the band was inarguably well into it by the release of Day Tripper in December of 1965.
While it was Bob Dylan that first introduced the band to marijuana during the summer of 1964, it was likely LSD, introduced to John and George in April, 1965 by no less a personage than George's dentist, that marked a transition in the band's style and, more importantly, perspective.
The middle period was a time of great hope and excitement, a time for unrestrained experimentation. The group still possessed the internal cohesion and direction of the early days, yet had much more of everything they needed to unleash their unbridled creativity - they had stopped their incessant touring and performed their last concert on August 29, 1966 and so could focus more time on composition, they had all manner of new technologies as well as the wherewithal to possess them, but most of all they indulged in the growing wave of hope and sense of endless possibilites that accompanied the era.
Most critics consider the work the band produced during this period their best. Quite an accomplishment considering that John Lennon was only 25 years old and Paul McCartney was just 23 when they entered the studio to record Day Tripper on October 16, 1965.
While the beginning of the period is not clear, one can almost certainly point to its end in February 1968 during the band's spiritual retreat in Rishikesh, India. Though the loss of their longtime friend and manager Brian Epstein on August 27, 1967 was a major factor in the band's eventual decline, it was almost certainly their disillusioning experience in India that marked a turning point. The summer of love was fading, by the time the band entered the studio in May of 1968 to record the White Album, the buzz had clearly worn off.