At first it might seem odd to want random numbers: that is, numbers in which no patterns can be found, which do not "say" anything. Yet it would be difficult to name a branch of science that does not rely, heavily or occasionally, on random numbers.

The most common scientific use for random numbers is in Monte Carlo simulations. A Monte Carlo simulation is any calculation that feeds random numbers into a set of deterministic rules (such as Newton's laws of motion) to model the outcome of a physical process. (Monte Carlo simulations are named after the city of Monte Carlo, famous for its gambling casinos.) Most real-world processes involve a random element, such as the arrival times of photons or of phone calls, the decay times of atomic nuclei, or the thermal jigglings of particles. In Monte Carlo simulations, therefore, the...