Vastu shastra is the textual part of Vastu Vidya and a traditional Indian system of architecture which literally translates to "science of architecture." These are texts found on the Indian subcontinent that describe principles of design, layout, measurements, ground preparation, space arrangement, and spatial geometry. The designs are intended to integrate architecture with nature, the relative functions of various parts of the structure, and ancient beliefs utilizing geometric patterns, symmetry, and directional alignments.
Vastu Shastras are ancient Sanskrit manuals of architecture. These contain Vastu-Vidya (literally, knowledge of dwelling). Vastu Shastras incorporate traditional Hindu and in some cases Buddhist beliefs. Ancient Vastu Shastra principles include those for the design of Mandir (Hindu temples), and the principles for the design and layout of houses, towns, cities, gardens, roads, water works, shops and other public areas.
According to Chakrabarti, Vastu Vidya is as old the Vedic period and linked to the ritual architecture. The emergence of Vastu vidya as a specialized field of science is speculated to have occurred significantly before the 1st-century CE. People who believe in Vastu shastra think that the universe is made of five things: Earth, Water, Air, Fire, and Space. They are a set of ancient rules given by our sages to improve the quality of our lives by proper use of these 5 elements of nature. Vastu Shastra represents a body of ancient concepts and knowledge to many modern architects, a guideline but not a rigid code.
The use of Vastu shastra and Vastu consultants in modern home and public projects is controversial. Some architects, particularly during India's colonial era, considered it arcane and superstitious. Other architects state that critics have not read the texts and that most of the text is about flexible design guidelines for space, sunlight, flow and function.
Of the numerous Sanskrit treatises mentioned in ancient Indian literature, some have been translated in English. Many Agamas, Puranas and Hindu scriptures include chapters on architecture of temples, homes, villages, towns, fortifications, streets, shop layout, public wells, public bathing, public halls, gardens, river fronts among other things. In some cases, the manuscripts are partially lost, some are available only in Tibetan, Nepalese or South Indian languages, while in others original Sanskrit manuscripts are available in different parts of India.