It is not humanly possible to write so many books.

Srila Prabhupada: “Are you reading sometimes my books? Which one?”
George Harrison: “Mainly Krsna.”
Srila Prabhupada: “That is the main book.” [laughs)
George Harrison: “Mukunda gave me the new books, but there’s so much to read.”
Srila Prabhupada: “Philosophy.”
George Harrison: “I don’t know how anybody could have written it, it’s is difficult to read all that amount”

Srila Prabhupada: “Sometimes, they are surprised how one man can write so many books, but it is Krsna’ s grace.  Otherwise, not possible. Human being, it is not possible

Srila Prabhupada conversations with George Harrison. London, England – July 26, 1976.
Srila Prabhupada explains why His books are so potent?
Srila Prabhupada explains that they are written by Vyasadeva.

Note: Srila Prabhupada repeatedly told us again and again that He did not invent a new philosophy or his own philosophy. He said that His books were simply the presentation of the message of the great Acaryas.
Srila Prabhupada: Thank you. You have read some of my books?

Guest: Yes.
Srila Prabhupada: They are not my books. I am simply translating. They are written by Vyasadeva, the original Vedic scholar. Srila Prabhupada lecture. Jakarta, Indonesia – June 8, 1976,
Srila Prabhupada explains that they are Krsna’s books.
Ramesvara: The only hope is to read your books.
Devotees: “Jaya.”
Srila Prabhupada: “Not my books, Krsna’s books.” Srila Prabhupada room conversation. Los Angeles, California -. June 8, 1976,
 
Srila Prabhupada will be remembered for centuries, making history.
Brahmananda: In the airport. And this caused big sensation, because never, even big Indian gurus have come to South Africa. Never have any whites bowed down. It was the first time whites bowed down to…
Srila Prabhupada: They clapped. After hearing me, they clapped. They purchased books. Now they are selling books. Some think my books are more important. We shall give more concentration for pushing and publishing. What do you think?
Devotee: Yes. That is our weapons. They are our strength, they are our guidance, and they are our ammunition. Everything is based on these books, everything. We are…
Srila Prabhupada: One Indian. a very learned scholar in Chandigarh, he has given very good certificate. What is that?

Devotee: “He said that ‘There have been many commentaries on the Bhagavad-Gita including Ramanuja, Madhva and Sankara,’ and then, he said ‘Tilak and Gandhi, but of all of them the commentary by A.C. Bhaktivedanta Swami is the greatest commentary. ‘Punjab University.’  Then he said later that ‘ In this suffering mankind, God has sent His Holiness A.C. Bhaktivedanta Swami