The central theme of the book alleges that atheistic Illuminism, through the infrastructure of Grand Orient freemasonry, driven by the ideology of the philosophes laid the foundations for a large scale, ongoing war against Christendom in general and the Catholic Church in particular.

The document claims that it had been manifested primarily through manipulating the outbreak of various radical liberal republican revolutions, particularly those focused on atheism or religious indifferentism in their anti-Catholicism.

[1] Some asserted vividly that the French Revolution was the result of a deliberate conspiracy or plot to overthrow the monarchy, the Church and aristocratic society in Europe, allegedly hatched by a coalition of philosophes, Freemasons and the Order of the Illuminati.

[2] Robison's book released in 1797 was called Proofs of a Conspiracy against All the Religions and Governments of Europe, carried on in the Secret Meetings of the Free Masons, Illuminati, and Reading Societies.

Some European countries also experienced a rise in clandestine radical groups like the Carbonari in the various Italian states and Fenianism in Dillon's native Ireland, which was then part of the United Kingdom with Great Britain.

We wish it to be your rule first of all to tear away the mask from Freemasonry, and let it be seen as it really is; and by sermons and Pastoral Letters to instruct the people as to the artifices used by societies of this kind in seducing men and enticing them into their ranks.

The original contains a foreword by an unnoted author, a letter of endorsement from Pope Leo XIII dated 6 September 1885 and one signed 'JOHN CARDINAL SIMEONI, Prefect.'

The first chapter has been lightly edited to remove spurious greetings and comments on the hall in which the speaker delivers his lecture as well as remarks on the establishment of local Catholic organisations.

Chapter XXIII, 'The sad fate of the conspirators', makes the claim that most Irish peasants refused to take aid from charities that demanded apostasy from the Catholic church, as part of its main theme that a righteous death is better than an unholy life.

The work was granted nihil obstat status on 3 May 1885 by W. Fortune of the Censor Theologus Deputatus and a licence to be printed, an Imprimatur, the following day by Gulielmus J. Canon Walsh, Vic.

In a letter dated 5 September 1885 and printed in the preface to the book, Leo XIII expresses his belief in the importance of the work and grants an Apostolic Benediction to its author.