I bought a copy of A Commentary on the Prefaces and the Eucharistic Prayers of the Roman Missal recently and started reading it yesterday. It's part of my research for my second book on the Mass, Praying the Mass: The Prayers of the Priest. It's out of print, but I bought a copy through Eighth Day Books. The book is by Msgr. Louis Soubigou, translated by Rev. John A. Otto in 1971 for The Liturgical Press. The content seems quite orthodox, and many of the comments in the text present a decent picture of the liturgical and reform-related turmoil of the late 60's and early 70's:
"Constant recourse to the official Latin text [of the Prefaces] is particular necessary in this commentary because it is a translation from the French. The author develops his observations from the official Latin readings and the French version, which normally remains very faithful to the original. After comparing the American ICEL version of the Preface of the Holy Trinity (page 144) with the original Latin text, one may decide for himself the degree of its fidelity." (Introduction, p. 4)
"P.S. This Preface [for the Sacred Heart] (and for that matter the feast as a whole) has its gainsayers among the 'litniks.' For them an aura of uncongeniality seems to haunt its thought and expression, particularly the effort 'to offer homage of reparation to the disdained and disregarded love of Christ.' It may be difficult to see how this motif fits into traditional liturgy — but why make this appeal to tradition when traditional liturgy as such is likewise being discredited and discarded?" (Preface of the Sacred Heart, p. 125)
I'm skimming the Prefaces; I'll be reading in detail the second part, on the Eucharistic Prayers. I recommend this book to anyone interested in learning about the doctrinal and spiritual content of the Prefaces and Eucharistic Prayers.