Scripture Online

Sri Chaitanya - reviver of Achintya Doctrine in Vedic Tradition -

Inconceivable Unity in Diversity - Teaching of The Golden Age that incorporates and reconnects all other teachings and traditions.

Sri Chaitanya Charitamrita depicts Chitanya's past times.

http://bvml.org/books/CC/

Achintya Doctrine from Advaita (monistic) perspective from Shiva.

Maha Nirvana Tantra

http://www.sacred-texts.com/tantra/maha/index.htm

Achintya Doctrine from Dvaita Dvaita (dualistic) perspective.

From Brahma:

A.C. Bhaktivedanta Swami Prabhupada is perhaps the greatest translator of Vedic Scriptures. He made a real elaborate work: transcript-transliteration-translation-comment. He definitely freed the world from concepts of Impersonal-ism and Void-ism, yet his body of work remains unfinished as He didn't freed the world from concepts of Dualism and Double Dualism traditionally carried by Gaudia sect. He did make a definite progress towards Chaytanya's Achintya doctrine, in comparison to his predecessors, yet most of the work in this field he left for future generations. One may not agree with every comment or even translation and being a genuine seeker one shouldn’t, but transliteration will take one closer to meaning even without knowing Sanskrit. Eventually you learn to see multiple meanings within the context and be even more capable seeing layers of deeper meanings and assemble your own translations and comments. Nobody before did such translation work. In fact this is the most transparent work on scripture ever.
One should start with Bhagavat Gita, Isopanishad, Srimad Bhagavatam, Brahma Samhita - those are classic esoteric texts-pure philosophy.

http://bhagavata.org/treasury/links.html