You might think it must be easy to define randomness, but nothing could be further from the truth. Not only is it difficult to create random events or sequences of numbers, verifying whether something that we have produced really is random is no easy task either. Many great mathematicians throughout history have examined the problem of randomness, but it was only a short while ago, in the era of computers and information technology, that the questions concerning randomness revealed themselves in all their complexity and appeal.