The Vedas comprises of four different types of widom for systematic progressive education , within these texts many different types of sciences are found , in summary of the body,  mind and consciousness and the workings of the responsive universe.

Artha sastra , Dharma Sastra , Jnana Sastra, and Bhakti sastra are the descriptions and categories of the Vedas covering everything that can be understood in details  , but also bearing in mind once one thing is known every thing is known , and that ultimately knowledge and relationships with Divinity are based on revelation in that was beyond intellectualism.

The ultimate Bhakti sastra analysis can be understood in this Bhagavad Gita verse 9.2.

rāja-vidyā rāja-guhyaṁ
pavitram idam uttamam
pratyakṣāvagamaṁ dharmyaṁ
su-sukhaṁ kartum avyayam

Translation

This knowledge is the king of education, the most secret of all secrets. It is the purest knowledge, and because it gives direct perception of the self by realization, it is the perfection of religion. It is everlasting, and it is joyfully performed.

The secret of all secrets is always based on open, honest, and loving relationships with absolute trust and surrender . By entering into an honest open relationship with Krishna and His associates , the secrets are revealed.

http://www.thevedicspectator.com