I have read both of his books on Jesus published since Joseph Ratzinger was made Pope Benedict XVI in 2005. His first volume to a life of Jesus (Jesus of Nazareth, 2008) spent a lot of time on the character and teaching of Jesus. This second volume, as one can tell by the subtitle, is a study on the passion, death and resurrection of Christ.
Certainly there are points of theological disagreement, but I will contend that a Protestant would have a difficult time reading these volumes and not appreciating the portrait of Jesus that emerges from the text. In what might possibly be a move to help with such schisms in our approaches to Jesus, Ratzinger provides a study which is spoken in unity and love rather than centering on our ecumenical divisions.
The book itself covers the final week of Jesus' life, from the not-so-triumphal entrance into Jerusalem until Easter Sunday. (An epilogue is provided to help bridge thought into Ascension and even Pentecost.) This is a good read for Lent and Holy Week, for it helps us to remember that there is so much more to be gained when we focus on the cross than when we simply look at ourselves.
From the perspective of biblical studies the book is good, but not great. Ratzinger has his pocket of scholarship from which he draws - most of which are quite solid, actually - but there are clear moments when appealing to other work would benefit his text greatly. For instance, any examination into the Resurrection without mention of N. T. Wright's extensive research into the area is almost painfully obvious. (But, then again, where are we on the whole Anglican-Catholic thingy these days?) Given the research that he does interact with, it would be natural/necessary to catch these pieces.
There is, however, some good theology found in this book. Notice that I do not say there is good 'Catholic' theology, for I suppose that if it is true about God then it is good theology without distinction. A few examples to help you get a feel for the book:
1. Ratzinger's examination of Jesus' high priestly prayer is quite good. He explains it this way, "'Eternal life' is thus a relational event . . . The relationship to God in Jesus Christ is the source of a life that no death can take away" (84-85). Throughout the book there is a clear focus not only on the knowledge of Jesus, but on the impact he has on the life of the believer (as well as the life of the church).
2. His work on the Last Supper is also interesting. It is a shame that communion is so vital to the church, yet so often goes without proper theological reflection. This has shifted very recently (see Pitre's work), but there is still more to do. Here, Ratzinger spends time on the breaking of bread motif in the Gospels, "It is also a gesture of hospitality, through which the stranger is given a share in what is one's own . . . God's bountiful distribution of gifts takes on a radical quality when the Son communicates and distributes himself in the form of bread" (129).
3. Further insight is given to the Last Supper-Eucharist connection by seeing it from the perspective of Jesus as God-Man. "This faithfulness of his means that he acts not only as God toward men, but also as man toward God, in this way establishing the Covenant irrevocably" (133). This certainly connects with the notion of Jesus taking the place of Israel when she could not achieve her own redemption, and also demonstrates (from one perspective) how this covenant in Jesus' blood has been brought to reality.
4. A final section to highlight is the Garden of Gethsemane. Ratzinger challenges the reader to consider Hebrews' title of Jesus as High Priest to help us understand what is happening in the hours before Jesus' crucifixion. "For these cries and pleas are seen as Jesus' way of exercising his high priesthood. It is through his cries, his tears, and his prayers that Jesus does what the high priest is meant to do: he holds up to God the anguish of human existence. He brings man before God" (163-164).
Those committed to understanding the Passion of Christ ought to read this book, regardless of what baggage might be sitting around regarding the Roman Catholic Church. There are times of theological wrestling and ecclesiastical disagreements, staunch and fiery as they may become. But when it comes to understanding Jesus - his life, teaching, love, suffering, death, resurrection, ascension - such things need to be put away. Especially today, when so many people who are lost and hurt and who don't care about that stuff anyway.
There is something to learn from this little book by Pope Benedict XVI, who is flawed and broken and searching and holy . . . just like every one of us.