Shambu Das to whom this letter is addressed, was a very talented musician and Ravi Shankar's right-hand man in 1966. Shankar put Shambu in charge of George Harrison's musical tuition and in December 1967, Shambu co-produced and arranged the Indian music sections of his soundtrack Wonderwall Music, Harrison's first solo venture.
It's interesting that Harrison refers to the Beatles' historic record All You Need Is Love in this letter. It was this song that the Beatles recorded on the first multi-national live TV broadcast on June 25th, 1967. BBC publicity described the Our World event as follows: ...for the first time ever, linking five continents and bringing man face to face with mankind, in places as far apart as Canberra and Cape Kennedy, Moscow and Montreal, Smarkand and Söderfors, Fakamatsu and Tunis.... The broadcast attended by a number of The Beatles' celebrity friends such as Mick Jagger, Keith Richards, Marianne Faithfull, Eric Clapton, Keith Moon and Graham Nash, was staged like a party, and was estimated to have a viewing audience of around 500 million from 31 different countries.