The official business philosophy of ISKCON explains how that their global distribution of their books  is the work of a good Samaritan. A deed in the tradition of Jesus feeding the 5000. Only this is"spiritual food", just as important for the soul as the bread for the body. They barely mentioned that this activity also happens to be the main source of financial income. Not thanks to brilliant sale routines or outstanding product quality, but rather just the lucky result of monks approaching people in streets,parks and airports. Fortunately for the Krishnas, some of them ended up accepting their books for some nickles, just to get rid of them as quick as possible. The books are probably never read in 9 out of 10 cases, if not dumped in the nearest trash can. It s basically the same act of pity, the same that makes you spare some change for a beggar on the corner or the mentally ill performing xmas carols in the shopping mall.
 Bhagavad Gita, Srimad Bhagavatam, Bhagavad Gita As It Is, Higher Taste etc.
The general fundamental idea behind their design for life is the philosophical notion of that "YOU ARE NOT THIS BODY". Humans are trapped in a world of maya, the sanskrit word for illusion,a material existence determined to follow the rules of the physical world. You are born,you live and you die. In the Veda,Hindu and Buddhist tradition this remains a never ending cycle of reincarnation. If you reach the level of human existence, according to your karma in previous life, there is possible to break this chain of death and rebirth by wising up, using your intelligence to reach beyond what s visible for the eye, engage in bhakti yoga,a transcendental meditation where the key concept is to recite the holy name in a mantra that will get you out of it and "back to Godhead",as they say. Chant "Hare Krishna" and you ll have your share of nirvana. So they abandon all concerns of what most people know as reality,from family life to material joy, prior to this uncertain promise of an afterlife with the blue god
Let s go back to the argumentation once again: If you re intelligent, you ll see "the truth", clear as the day: you are not your flesh and blood. It s an illusion, an illusion named reality. Without committing to a broader discussion on the construction of the human soul,there s at least space enough to take the following example under consideration: Say you re a child, who grows up without any notion or concept of an abstract soul and hence not familiar with neither the Vedas,the bible, Platon,Descartes,Kant or Freud. With the coming of age the real intelligence will in fact land at the opposite view of the Hare Krishna. "I AM THIS BODY"
Any other explanation requires you to, as Danish philosopher Søren Kirkegaard says, take a step out from the cliff, in this case the body. Intelligent choice,Prabhu, to build your god damn temple in thin air instead of the only cliff you can be certain exists for a fact. Personally, I think humanity would be far better off if we move away from the metaphysical schizophrenic project, in religion as well as psychology, concerned with the task of extracting the soul fromits´corpus. The split into different non corporeal abstract entities slowly alienates the life of the mind from the life itself. And life is,like it or not,THE BODY.