Christian Liturgy by Frank C. Senn. The book is rather large and spends quite a bit of time on the Reformation and the modern ecumenical movement. I wish a little more time were spent on the early church, especially the Eastern church and the liturgy of St. James. Overall the book is very good especially when it is being descriptive. When it is being prescriptive it misses the point. It seems that Senn has his daily conversations most often with people in other denominations who are members of some type of ecumenical movement but very little with confessional Christians. Or perhaps Senn is trying to avoid the real arguments and divisions. On page 479 Senn writes:
Lutherans need to understand that sacrifice is a polysemous concept in the eucharistic tradition that refers variously to the offering of bread and wine, the self-offering of the faithful, and the saving work of Jesus Christ. Roman Catholics need to remember that sacrifice is one metaphor for the saving act of Christ along with others, such as ransom or purchase, victory over sin, death, and the devil, and the restoration of immortality through the incarnation of the Word. All of this is present in the eucharistic tradition. Study of this tradition would go a long way in helping us to overcome the ecumenical impasse on eucharistic sacrifice in particular and on the eucharist in general.
Sacrifice is one methaphor for the saving act of Christ? Confessional Roman Catholics and Lutherans would agree with one another that Christ's sacrifice is not just some metaphor for the saving act of Christ, nor are ransom, purchase, victory over sin, death, etc. Senn wants to overcome the ecumenical impasse by turning everyone into theological liberals that view everything as some metaphor. He calls us to study the eucharistic tradition but deny the original intent of the writers and read everything through modern liberal eyes. The real dispute between Roman Catholics and Lutherans is over whether the eucharist is a propitiatory sacrifice. Roman Catholics say yes. Lutherans say no. Senn says yes because he thinks that even the death of Christ on the cross was only a sacrifice metaphorically and denies real propitiation completely.
The above is just one example. Senn does the same thing with Lutheran and Reformed disputes on the eucharist. This book can be very useful, but the reader should be cautious when reading Senn's prescriptions.