The art of fortification had reached a high state of development even at the dawn of Indus Civilization in India. Powerful military works have been noticed in the excavation conducted at various sites of the civilization. The system continued uninterruptedly in the following period. There were naturally variation of form in several centuries consequent on difference of concept. As a result of pressing circumstances and religious injunctions every ruler regarded it his sacred duty to construct a fort. As a result of this zeal the land was studded with fortified structures. The book Military Architecture in Ancient India traces the development of the art of fortification right from the period of Indus Civilization upto the period of emperor Harsha Vardhana. It also deals exhaustively with various aspects of fortification of different periods of Indian history giving an account of famous forts of ancient India based on excavation and literary sources. Subjects like components of fort structure, arms and armaments, methods of attack and defence and history of fort warfare have been discussed in detail.