That is the real preaching, selling books. Who can speak better than the books? At least whoever buys, he will look over. If you have to sell books, do it by hook or by crook. The real preaching is selling books. You should know the tactic how to sell without irritating. What your lecture will do for three minutes, but if he reads one page his life may be turned. We don’t want to irritate anyone, however. If he goes away by your aggressive tactics, then you are nonsense and it is your failure. Neither you could sell a book, neither he would remain. But if he buys a book that is the real successful preaching. That is the certificate of my Guru Maharaja, if someone, brahmacari, would sell a one paise magazine, if one of our brahmacaris would go and sell a few copies, he would be very very glad and say “Oh, you are so nice!” So distribution of literature is our real preaching. Now if you cannot handle the matter nicely, that is your fault. But the success of your preaching will be substantiated by how many books are sold. Anything you want to sell, you have to a little canvass, so he gives some money for the service of Krsna. That is his good luck and he gets the chance to read some transcendental knowledge. But if you only irritate and he goes away, that is your less intelligence.

From Srila Prabhupada’s letter to Bali-mardana — Los Angeles 30 September, 1972