Rabbi Irving Greenberg published early in the 1980s three essays that brought about much new and revolutionary thinking. He delineates in clear terms his reading of Jewish history and extrapolates from this his projections for the future of Judaism in a radically and fast changing world.
These essays have been bundled and published by the organisation he founded called CLAL under the title Perspectives. Below you will find three links taking you to the essays as PDF-files. they should be regarded and read as one whole.

Part I:   The Third Great Cycle of Jewish History 
Part II:  Voluntary Covenant
Part III: The Third Era - Power and Politics