The name “Monte Carlo” emerged from the name of the city “Monte Carlo”, famous for its Casino. In the casino there was a roulette where a small button was fixed at the centre of a wheel and the numbers 0–9 were marked at the end of the ten spokes of the wheel. When the button was pressed, the wheel starts rotating. When the wheel stops, a number within 0–9 was marked by a marker. Depending upon the number near the marker, one had to play the game. Thus this mechanical device was the device, first constructed to generate random numbers. The method was theoretically came through the work “The Monte Carlo Method” published by American mathematicians John Von Neumann and Stanslav Ulam in 1949. In spite of the theoretical background this method could not be used in significant scale until the invention of electronic computers. There are two aspects of this method. First it is used to simulate any process whose growth is affected by random factors and second to solve mathematical problems not affected by random factors but can be connected to artificially constructed probabilistic model giving rise to solution, otherwise unavailable. For example, suppose we are to calculate the area A within a unit square in Fig. 10.1. © Springer Science+Business Media New York 2014.