Vastu Shastra is the Vedic study of architecture, which follows certain principles and is aligned with certain beliefs. It is akin to the Oriental belief of Feng Shui. Vastu rests on the conception that every living and non-living thing on Earth has a soul. And souls react to the magnetic forces covering the Earth. By following Vastu principles people believe they stay in harmony with the cosmic energy, thus positively affecting their lives.
Interestingly, Vastu states that matter is made of five basic elements. They are earth, water, fire, wind and ether or vacuum. These elements can be recognized as the basis of many types of beliefs. The already mentioned Feng Shui is one of them, and the other is of course astrology that also has 'fire', 'water', 'earth' and 'wind' signs.
So, if one wants a house to aid in the general well-being, health, happiness and prosperity of its occupants, then Vastu Shastra is one of the ways in which this can be done.
Vastu dictates how your house should be built, what direction the doors and windows should open, what are the ingredients that should or should not be used in the construction of certain rooms, and what furniture should be placed where in the house. To sum it up, one can easily leave it upon Vastu to design and set one's house!
The concepts of Vastu rely on the tenets that combination of aforesaid elements can be made to aid in one's over all well-being in the world. Hence, advices may range from refraining to use river-mud while constructing one's puja-room, or placing the bed in the bedroom in a North-South direction. And if a river flows in the vicinity of the house, then what should be the direction of the rooms and doors and windows.
While a number of Vastu instructions can be explained scientifically, some ambiguities remain, which can easily be credited to the long time-difference between the era in which it would have been created and the present age.
As can be seen, Vastu covers a major part of one's lifestyle. And as it happens with every all encompassing subject, the followers of Vastu are many. Builders take care to follow the advice of Vastu-gurus before finalizing a design for any prospective building, as a considerable number of buyers and clients tend to follow Vastu Shastra.
The ancient science is so popular among some firm believers that it can become a matter of deciding upon the sale or rent of any major architectural construction. This makes Vastu a major mover of market and real estate dealings. All in all, Vastu Shastra is an important moving force in Indian architecture, and major parts of the clientele consider the Vastu-friendliness of the dealing.