When the vedas was first spoken by Lord Brahma (the first created being of this universe), it was understood by his sons in different ways. Later, Mahamuni Vyasa took birth to translate these esoteric timeless sound into text format especially favoring kali yuga residents. Vyasa also wrote the succinct version of the vedas by taking its conclusions and coding it in short texts called the sutras. Because it contained the conclusive truths in coded form, it was called vedanta sutra.
Later, a great saint some 2000 years ago by name Adi Shankaracharya wrote a commentary on the vedanta sutras called the sariraka bhasya. Today, most if not all of hinduism follows this version of the vedanta sutra. Western scholars who study hinduism define hinduism based on the interpretation of Shankara's sariraka bhasya commentary. The philosophy pushed forward by Shankara is called Advaita vada where in the ultimate sense, everything is one called brahman. The varieties we see in this world is simply an illusory transformation of that non-distinguisgable brahman. Hence, one can adhere to any ishta-deva and still attain the same destiny as anyone else in brahman. Later, famous people such as Ramakrishna, Chinmoy, Vivekananda, Aurobindo etc and the likes basically presented their flavor of Adi Shankara's sariraka bhasya. This is the understanding of hinduism today by hindus and non-hindus.
The fact, and the more serious students must be aware, is that there are more sophisticated commentaries than sarirak bhasya presented by Ramanuja and later by Madhwa. Unfortunately, their commentaries of the vedanta sutras are not as popular as the Advaita vada of Shankara. Srila Prabhupada's teachings come in the line of these two saintly people. In this teaching, the ultimate reality is dual - Supreme Being Ishvara or God and the subordinate being jiva or soul. As per the dualistic philosophy (dvaita vada), Vishnu or Narayana is the Supreme. He is a Person with attributes. He is the creator, maintainer and destroyer in the ultimate sense. All other devas, and the universes are subordinate to His ordain.
The dualistic commentary of the vedanta sutra is a natural commentary as opposed to the massaged commentary of Shankara. It is natural because it is harmonious with the world around us and has no contradictions. Anyone interested in hinduism in a real way should study dvaita vada commentary of vedanta sutra and understand the religion in that way.