Alternative interpretations rejected by the author include the notion that the Kingdom is identical to the Church, to a temporal empire such as Byzantium, or that it is “within us” in a spiritual-mystical sense. However, Viviano is also uncomfortable with the combination of utopian thinking and apocalypticism, apparently preferring a more “reformist” approach to solving society's ills. He also rejects liberation theology as too Marxist, quoting Joseph Ratzinger's criticism of the same. The Social Gospel is also up for criticism, since it completely forgets the eschatological-apocalyptic perspective in favour of purely this-worldly reforms.
I don't think this little tome is suitable for the general reader, but it could perhaps be a good introduction to the problem for theology students. The book ends with an extensive literature list for further study.