Sri Tripura Rahasya is an ancient work in Sanskrit. It was considered by Bhagavan Sri Ramana Maharshi as one of the greatest works that expounded advaita philosophy. Some scholars however call this system the Taantri or the Saakta, and point out some apparent differences between this and Advaita Vedanta. This system teaches that the Supreme Reality is no other than Abstract Intelligence. "Intelligence" signifies Self-luminosity and 'Abstraction' denotes its unlimited nature.
Bhagavan Sri Ramana Maharshi often often quoted from it and regretted that it was not available in English. As a consequence Sri Munagala Venkataramaiah (now Swami Ramanananda Saraswathi) took up the work of translation in 1936 as another labour of love, adding just one more English translation to his already extensive store.
The origin of this work is as follows. Mahaadeva (Lord Siva) originally taught the Highest Truth to Vishnu who in turn taught Brahma in the Celestial regions. Later Vishnu incarnated on Earth as Sri Dattaatreya, the Lord of the Avadhuutas (the naked sages), and taught it to Parasuraama with the added injunction that it should be communicated to Haritaayana who would later seek the Truth from him. The work was thus written by Haritaayana and is also called after his name Haritaayana Samhita. It is said to consist of 12,000 slokaas in three sections.
You can read this great work of philosophy in English at http://sss.vn.ua/tripura1.htm5