I am very glad to hear all the good news, especially that you want to sell books more and more. That is the best preaching work; each book sold means there is some practical effect of preaching, there is some tangible progress. So try to sell books as many as possible in your country, and in this way, so long you remain active but not for your personal sense-gratification, so long you remain active only satisfying Krishna's senses, then this movement will be successful without any doubt. As soon as someone wants to satisfy his own senses, then he fails at everything.
Letter to Kurusrestha, 23 November, 1972