The history of Indian philosophy dates back to the time before the Christian era. In particular the development of Indian Madhya-maka spans more than 1000 years. The comprehensive treatment and systematic analysis of its entirety is so far unwritten and largely remains the goal of future endeavour. However, the first substantial building blocks towards this are specific monographic studies that try to explore the relatively uncharted territory of the history of Indian Madhyamaka.The present work, an edition of the Ma-dhyamakahrdayakarika I-III. 26 and an edition and translation of the Tarkajvala I-III. 26, is a contribution to this end. It provides an insight into the major work of an Indian Ma-dhyamaka propounder, Bhavya/Bhavaviveka, who exerted an intellectual influence far beyond his own time in the 6th century A.D. The Madhyamakahrdayakarika (dBu ma¿i sñin po¿i tshig le¿ur byas pa) is considered an authentic work. It is one of the earliest doxo-graphical works that has survived to us and is one of the reliable sources on the history of early Indian philosophy. The only available commentary to it is the Madhyamakahrdayav-rtti Tarkajvala (dBu ma ¿i sñin po¿i ¿grel ba rTog ge ¿bar ba).The present study of these two texts includes all available primary sources: The text of the Madhyamakahrdayakarika as preserved in three Sanskrit sources, collected over a span of more than ten years; and its Tibetan translation together with that of the Tarkajvala both executed by the Indian scholar-monk Atisa and his Tibetan collaborator in the llth century. Both texts are examined as transmitted in five editions of the Tibetan Buddhist canon and their interrelationship with the Sanskrit sources is investigated. The Tibetan translation of the Tarkajvala is the earliest accessible source for the lost Indian autograph.The reader can therefore follow the well structured outline by a Madhyamaka proponent of a Buddhist path that leads to the knowledge of reality (tattvajñana), i.e. the first transworldly stage of liberation.The first three chapters of the Madhyama-kahrdayakarika and Tarkajvala constitute an integral thematic unit. The three constituents of a Bodhisattva's mind of enlightenment (bodhicitta) - love, compassion and knowledge - are elaborated with scholarly skill and poetical finess in the first chapter. The ethics (vrata) of this Bodhisattva abiding in the nirvana-without-foundation (apratisthitanirvana) are the main theme of the second chapter: An array of his virtues saturated with his altruistic aspirations is displayed as well as compared to those of brahmanical practices. The author's philosophy is mainly introduced in the third chapter with his view of the two truths (satyadvaya) based on scriptual authority and reasoning. Tarkajvala III. 1-26 discusses not only the twofold (conventional and absolute) insight (prajña), but also introduces the prerequisites for obtaining knowledge of reality, meditative equipoise and the author's mode of reasoning developed on the basis of the logico-epistemological school headed by Dignaga.