Opposite of the dystopian society, the utopian society is a literal heaven on earth. The ancient civilization of the Babylonians was thought to be a paradise, as well as the mythological city of Atlantis.
Unlike the dystopian society, the utopian society is harder to imagine, as everyone's idea of paradise is different. There would always be some disagreement between the people, and therefore the utopian society is impossible to obtain.
A few example of novels with the theme of utopian society are William Morris' News From Nowhere, and H.G. Wells' Time Machine