Inflationary Models of the Early Universe

The inflationary models of the universe provide new avenues at the interface of particle physics and cosmology, potentially leading to solutions to some of the most difficult problems in both cosmology and particle physics. Numerous proposals have been made to account for the recent cosmic acceleration of the universe, either by adjusting the gravitational sector of the action or by introducing exotic matter into General Theory of Relativity. Different inflationary models especially old inflation, new inflation, chaotic inflation, power law inflation, along with the conditions required for inflation are discussed here with their merits and demerits. I also discuss the recent developments of inflationary models taking into consideration of the present cosmic acceleration of the universe.