The Navya-nyaya, which has heralded a new era in the system of Nyaya in India, has brought a revolutionary change in the out look of the Nyaya Philosophy. It has systematized all the doctrines of Nyaya and Vaisesika under the single head of 'means of knowledge' (Pramana). The Thought Jewel of Reality (Tattva cintamani), which is the most fundamental work of the Navya-nyaya, is composed by Gangesopadhyaya of Mithila and it deals with all the important doctrines of the Nyaya-Vaisesika, i.e. Philosophy, logic, epistemology, and linguistics, under the four books, viz. Perception (Pratyaksa), Inference (Anumana), Analogy (Upamana) and Word (Sabda). It has set a distinct standard for the scholarly discussion in the 12th and the 13th centuries in India. Inference, the Anumana Khanda of the Tattva Cintamani, is divided into thirteen chapters such as i) description of inference, ii) theory of pervasion, iii) means of knowledge of pervasion, iv) theory of reduction-ad-absurdum, v) generalization of pervasion, vi) comprehensional relation characterized by universal, vii) theory of condition, viii) the state of occurring in the subject, ix) consideration, x) purely positive inference, xi) presumption, xii) members of syllogism and xiii) theory of fallacious probans. Thus, the present work provides a comprehensive view of all the aspect of inference. Also, the present work, with general introduction, Sanskrit text and English translation with explanation, is the most authorative manual on the Navya-nyaya theory of inference.