In this book, Ratzinger tackles the big issue of the end times and all those issues which go with it:
i) including the seriousness of history and the development of doctrine given the biblical data provides a sketch of life after death but hardly explains in toto what happens to those who die before the parousia, there is an excellent overview of the data of the Old Testament which clearly shows a development in understanding
ii) the importance of philosophy and the breakthrough made by St Thomas Aquinas in fusing platonic and aristotleian thought so as to arrive at the conclusion that the soul is the form of the body,
iii) the immortality of the soul, which curiously underpins the resurrection of the body;
iv) the rejection of resurrection into death as contrary to the facts and also contrary to taking history seriously; curiously embracing such a docrine imperils resurrection itself as resurrection then becomes a new name for the soul! Also, look at the pastoral effect of telling the mourners at the funeral that the man lying in the coffin is risen despite the evidence!
v) the apparent rupture in catholic theology, which discarded many long held beliefs including immortality of the soul - a change in attitude towards tradition;
vi) the reasonableness of belief in heaven, hell and purgatory.
vii) the importance of faith being in harmony with reason and vice versa ( aver important theme for B16 - Regensberg address for one.
viii) Liturgy as anticipated parousia - the Eucharist, God with us but not yet
ix) christology as key to the evolving doctrine of life after death
But, the key point one comes away with is the centrality of communion to Ratzinger's thought - for Ratzinger, everything hangs on communion - God is communion, we are made in his image and are thus orientated to communion - there cannot be eternal bliss until all the body of Christ are gathered into communion at the end of time where God will be all in all.
"But his final place for us in the whole can be determined only when the total organism is complete, when the passio et action of history has come to an end. And so the gathering together of the whole will be an act that leaves no person unaffected. Only at that juncture can the definitive general judgement take place, judging each man in terms of the whole and giving him that just place which he can receive only in conjunction with the rest (Ratzinger, Eschatology, 190)
Finally, if this book has been to your liking, I would also recommend "Introduction to Christianity" and "The Spirit of the Liturgy" and his "Jesus of Nazareth" (as Benedict XVI) - these represent Ratzinger at his best.