The Concept of Merit in the Western Rite by Fr. David John William McCready
 
This is a controversial book! Against the oft-heard assertion that merit is a heterodox word and concept, it argues that merit-language forms an integral part of the heritage of the patristic West, being used by such great Orthodox saints as St Cyprian, St Ambrose, St Leo, St Benedict and St Gregory the Dialogist. It further argues that their teaching is reflected in that of the Greek Fathers, such as St Basil and St John Chrysostom, as well as in the later Byzantine tradition. Included is a discussion of the controversial term, satisfaction.
 
The second part of the book looks at merit language in the Roman ('Gregorian') Mass, concluding that this language should be retained in the Western Rite as a fundamental part of the occidental tradition.