Bharat muni  completed his Natya sastra , a study of the rasa of mundane love.
Srila Rupa Gosvami adopted some of the rasa explanation  of Bharat Muni to explain the origins of unlimited rasa  of the spiritual realm from the reflected version that we find in the material worlds , both  in higher , middle and lower planetary systems explained in the fith Canto of the Srimad Bhagavatam.  Rupa Goswami intentions were  to give some hint of spiritual rasas and  tastes  of  a spiritual body with spiritual mind ,intelligences, and spiritual senses.
So  the technical sneha , mana ,  pranaya , raga , anuraga and bhava principles that are explained  by Bharat Muni  and adopted by Rupa Goswami but the further and higher realms of pure prem and  mahabhava..have been added , this higher explanation of rasa is  introduced by Rupa Goswami to take the subject beyond the conception of material rasa  that’s experienced to a limited degree and he is bringing us to the unlimited trancendental rasa displayed in Vraj , wherein the 64 excellences of spiritual unlimited qualities in relationship are displayed that are ever increasing and are experienced as ever new .

Purport of this is that, Rasa is the very essence of Godhead and although in the pre-Caitanya era different Bhakti Rasa Sastra were written, the special gift of Mahäprabhu is the form of brilliant amorous devotion in allegiance to the beautiful girls of Vraja is now being preached and presented to the world by Rüpa Goswami in his books Bhakti Rasamrita Sindhu, Ujjvala Nilamani, Vidagdha Mädhava, Lalita Mädhava . That amorous mellow of Vraja that was previously inaccessible to Brahmä, Siva, Uddhava and any other Saint of Demigod is now, by Mahäprabhu’s grace, described by the (wise seer) of Vraja rasa, Srimad Rüpa Gosvami, in his Rasika books and dramas. THE followers of Rupa and Ragganatha das should be consulted for full understanding of this topic .

The World wide society ISKCON founded by AC Bhaktivedanta Swami Prabhupada, under the order of Srila Bhaktisiddanta Sarasvati Goswami , who was under the order of Srila Bhaktivinod Thakur is currently in the business of distributing the knowledge of Rupa Goswami wholesale, all over the world.