This ontology on the topic of "Vaishnava" was first compiled in the book Gaudiya Kanthahara, under the chapter Vaishnava-tattva, by Srila Bhaktisiddhanta Saraswati Thakur Prabhupada.
If we try to understand everything in relationship with Krsna, then we understand vastava, reality. That is reality. If we study something minus Krsna, that is not real knowledge. Actually, Krsna is the original cause of all causes. Sarva-karana-karanam. So unless we come to the point of Krsna, any understanding, any knowledge is imperfect.
"A brahmana who is expert at chanting the four Vedas is not dear to me, but a devotee who comes from a family of dog-eaters is dear to me. Whatever he touches becomes pure. That devotee, although born in a family of outcastes is as worshippable as I am." (Itihasa Samucchaya)