Bio-deterioration of stone works is mainly due to bio-film formation, bio-corrosion caused by organic and inorganic acids, redox processes on cations from the mineral lattice and physical penetration by microbial communities. Our cultural property or stone monumental structures and other ancient buildings are particularly susceptible to these factors. As usual growing on the surface of stone monuments, various microorganisms also colonize the interior of the stone matrix. Lichens and fungi can cause serious degradation and deterioration by physical penetration of the micro organism. Fungal hyphae are able to penetrate deeply beneath the stone surface, leading to mechanical deterioration and degradation. The problem of deterioration and weathering of the monument is particularly relevant in countries like India where monuments are rich in cultural heritage. The book entitled Mycological study and Scientific Conservation of Historical Monuments is the outcome of my research work of various historical monuments situated in different states of India. The main subject of this work is to study the micro fungi community on monuments by using culture growth and microscopic observations in order to evaluate the potential damage caused by fungal species and then undertake chemical conservation as well as eco-friendly conservation by extract of medicinal plants. This book focused about the scientific investigations on the subject of bio-deterioration of cultural heritage through discussions on the extent of the problem, available preventive and remedial treatments, and current research based on isolation and identification of fungal flora on the monuments and their conservation by chemically as well as natural herbal product like medicinal plant extract of various plants. Preservation of this material from fungal deterioration by using safe or eco-friendly fungicide was the prime goal in this work. By the application of these new substances there will be no harmful to the stone surface of the monuments i.e. no change of the colour and without reaction with its stone components. This book has concentrated on the elimination of microorganisms from selected archaeological monuments of India and their conservation and preservation with chemical as well as eco- friendly chemicals extracted from medicinal plants.