Apparently the ex-Father Desanctis has the following credentials : born in a RC family, 22 years in a Congregation of priests associated with Jesuits. He was Confessor in Rome for 15 years. He was 8 years the parsih priest of Church of the Magdalene in Rome.
I am not so sure if his boook can be classified as another conspiracy theory that proposes the notion that the Jesuits have a program to win back Protestants to the Pope. I judge a book by its contents not by what it says in its cover. The reason why I like to study this book is because some of the the things he said in his Preface rings true to my experience.
Here is an example. I have often said and observe to the ex-Prots that the RC you see in western countries is not the same thing you see in Latinized countries like the Philippines, Mexico, Venezuela etc. I say this as a person who was also raised Roman and was devoted to the practice of the 7 sacraments and devotion to the saints. Remarkably here is what Desanctis says in p. 4.
He who wishes to know Roman Catholicism as it is, must study it in Rome, and study it, not in books, but see it in action in the Pope, in the Cardinals, and in the Roman congregations. Books often give a false, and always an incomplete, idea of Roman Catholicism. One finds in books either the barbarous and superstitious Papacy of the Middle Ages, or the poetical Papacy of Chateaubriand.
If you observe the Papacy in different countries, you will find it most varied. In the south of Italy you will still find all the superstitions of the medieval age; in England, and in Germany where Roman Catholics are mixed with Protestants, you will find a Papacy less superstitious and more tolerant, to be transformed into superstition and intolerance in the day when it shall have become dominant
Back home, when someone wants to have a child baptized, you will be asked in the church office if you want special or regular baptism which implies that the fee for the special one is dearer than the one for the regular one. In p. 6 Desanctis writes with strong words...
To know that Roman Catholicism is the religion of money, you need to go to Rome, to enter the Chancery, and the Roman Court of equity, and to see in what way bishoprics, canonries, benefices, matrimonial dispensations, and all spiritual favours are bought, to see how the price is haggled over, and to see a class of persons authorized to be the agents of such sales, under the specious title of Apostolic Commisioner.
There are fanatics on both sides of the divide, Desanctis does not seem to be one of them for he writes that he does not want to be controversial and he does not deny that there are good people who are RC and honourable in character. He does not deny that there are people who are acting in good faith but he does contend that it is an effect of culpable ignorance and keeping to pursue childhood prejudices (p.6). Amazingly, I recall my prejudices when I was a young lad.