Now Krsna gave us a little knowledge, which is known as Bhagavad-gita, and five thousand years ago this knowledge was given, but is still going on, all over the world. In our movement we sell Bhagavad-gita the most. Is it not? We sell our Bhagavad-gita As It Is everywhere and in large number. Because it is full knowledge, not partial. Everything is complete. Can you show any book in the world which has so much sale and which is so much perfect? There is no book. And I am not…, because we are Krsna devotees we are eulogizing like that, but any scholar, any philosopher, any scientist will say like that: “Oh, there is no comparison of this book.” I do not know exactly, but one gentleman told me that Professor Einstein, he was also reading Bhagavad-gita daily. Hitler was reading. Such, such big, big men. But I know many scholars, even Muhammadans, they also read Bhagavad-gita.

Srila Prabhupada; Lecture on SB 1.9.3 — Los Angeles, May 17, 1973