In this article I have introduced some of the facets of inflation in a fairly simple manner. If you are interested in going beyond this, then the inflationary production of perturbations is reviewed in Ref. [21], inflation and structure formation in Ref. [2] and particle physics aspects of inflation in Ref. [10].
At present, inflation is the most promising candidate theory for the origin of perturbations in the Universe. Different inflation models lead to discernibly different predictions for these perturbations, and hence high-accuracy measurements are able to distinguish between models, excluding either all or the vast majority of them.
Since its inception, the inflationary cosmology has been a gallery of different models, and the gallery has continually needed extension after extension to house new acquisitions. In all the time up to the present, very few models have been discarded. However, the near future holds great promise to finally begin to throw out inferior models, and, if the inflationary cosmology survives as our model for the origin of structure, we can hope to be left with only a narrow range of models to choose between.
Acknowledgments
The author was supported in part by the Royal Society.