Inflation is no doubt a leading theory of the very early Universe. It provides a satisfactory explanation to such diverse observations as that of flatness of the Universe or a scale-invariance of the density fluctuations. Its predictions have been found consistent with a range of observables probing the Universe from the largest, e.g., Cosmic Microwave Background anisotropies, to the very small ones, say, Lyman-alpha forest. However, when looked upon in more detail, inflation is not what one might have wished for, i.e., a consistent well-defined model, but rather a bundle of diverse, specific implementation of the inflation's generic ideas. This has led some to refer to inflation more as a paradigm, i.e., a framework within which to think of the early Universe, rather than a scientific model.
