J. C. Chatterji's book is a brief introduction to the nature of ultimate reality and the manifestation of the universe according to the Trika System. It also covers, briefly, the history of this advaita Shaiva philosophy of Kashmir. First published in 1914 as the first book in "The Kashmir Series of Texts and Studies," it is still the clearest introduction to the Tattvas of the Trika. Since the lower twenty-five of the thirty-six Trika Tattvas represent the entire universe from the Samkhya point of view, here also is a very clear exposition of the Samkhya Tattvas. The only difference is that, while the Purusha and the Prakriti are the final realities for Samkhya, they are but derivatives according to the Trika, which, carrying the analysis further, recognizes eleven additional Tattvas above the Purusha.