Here are just a couple of excerpts from the beginning of his piece:
...the motive for a particular preparation by the priest before Mass and a thanksgiving afterwards are of benefit to the whole Church because a priest who sanctifies the Christian people needs himself to have been filled with the Spirit of holiness. It always helps a priest if he has taken a moment to consider the texts he will pray during the Mass on that day... A priest who fosters personal silence in the time before and after Holy Mass will, by his disposition, encourage meditation.
[...]
The preparation of a priest for Mass will have been underpinned by the cycle of Liturgy of the Hours which enriches the life of any priest. The age-old wisdom of the Ritus Servandus in Celebratione Missae, still to be found in the early part of the Missal of 1962, presumes the intrinsic importance of the Divine Office for the inner life of the priest... the General Instruction of the Liturgy of the Hours carefully explains the connection between the celebration of the Eucharist and the Liturgy of the Hours: "Christ taught us: "You must pray at all times and not lose heart" (Lk 18:1). The Church has been faithful in obeying this instruction; it never ceases to offer prayer and makes this exhortation its own: "Through him (Jesus) let us offer to God an unceasing sacrifice of praise" (Heb 15:15). The Church fulfils this precept not only by celebrating the Eucharist but in other ways also, especially through the Liturgy of the Hours.
[...]
Any comparison of the specific texts offered for the Praeparatio will note that the same prayers are included in both forms of the Roman rite though they have been reduced to four since the Missale Romanum of 1970. In the Missal of 1970 these prayers consist in a prayer 'Ad Mensam' of St Ambrose, the prayer 'Omnipotens sempiterne Deus, ecce accedo' by St Thomas Aquinas, a prayer to the Blessed Virgin Mary 'O Mater Pietatis et misericordiae' and the Formula of Intention, 'Ego volo celebrare Missam'.
