Regarding the prophecies of St. Malachi: Proponents of these prophecies regarding the Popes point out that they have been surprising accurate to the point that they cannot simply be a matter of chance. Opponents point out that many of the prophecies have been so obscure, that it would be almost impossible not to find a believable link between the prophecy and the Pope whom it supposedly predicted. Opponents further highlight the fact that the prophecies seem to be fraudulent, i.e. they postdate the time of St. Malachi, while supporters point out that it technically does not matter what the particular human provenance may be of prophecies, as long as they are true. And for those who do not know the immediate relevance of this issue, you may find it unnerving to know that according to these prophecies, there may possibly be only one last Pope before the end of the world. I say "possibly" because there is no consensus on whether there is supposed to be some passage of time between one of the last Popes and the last Pope. For those who argue there is no passage of time, the Pope about to elected may very well be the last one in human history if we take the prophecies literally.
My take on all this: I don't think anyone knows for certain whether the prophecies are true or not, since apart from a direct revelation from God, it is impossible to construct a litmus test to measure their degree of veracity or fiction. This being said, I do not think it matters one bit whether they are true or false. I'll explain more in a moment, but allow me to move on to the topic of prophecy in general:
There are several reasons why I think it is a waste of time to read prophecies about the "end of times", and an even greater waste of time to devote time writing books about them. Keep in mind everything I am saying relates to non-biblical (that is, non-inspired) prophecies.
1. By their very nature, prophecies are notoriously difficult to interpret. If you do not believe me, take a quick read through the Book of Revelation with 20 other people and ask each what is going on. You'll likely have 20 different answers.
2. By their very nature, things seen in future prophecies change in accordance with the present moral and spiritual situations of the world. Remember the Book of Jonah? God declared that Nineveh would be destroyed - it was a prophecy by God of a future event. Yet something remarkable happened: all the people, from the greatest to the least, repented of their sins and thereby averted the outcome that was originally predicted. So much for the "it is written" mentality for prophecies.
3. Prophecy seems to have a few things in common with conspiracy theories, and this fact alone is enough to raise our suspicions. They both encourage distrust of rightful authority; they both tend to cause unhealthy fear; and they both endure because they are money makers in the form of books.
4. Everything we need to know has already been given to us and entrusted to the Church through Divine Revelation. We do not *need* private revelation, much less fear-mongering prophecies of a yet uncertain future.
5. Fixation on hard- to- decipher and/or false prophecies can absolutely bankrupt our spiritual life by taking our focus away from the Bible, the Magisterium, and the Sacraments, and replacing them with superstition and fear.
6. Let's get real: if we are living our faith as we really ought to, then we should be ready for any day to be our last day on earth. So if the end comes tomorrow, so be it! All the faster to attain the purpose for which we have been created! And if we as the human family need to wait a few more millennia, well, so be that as well. We should not look with fear or trepidation to the End (whenever that will come), but rather be joyful that when it comes, the entire cosmos will finally reach its recapitulation in Christ our Risen Lord.
So let's do ourselves an enormous spiritual favor this Lenten season: let's throw the prophesy books into the fireplace (if they help to warm the house, then they are at least good for something!) and take the time that we would otherwise be reading those books and use it to prayerfully read the Bible, the Catechism of the Catholic Church, and the Documents of Vatican II (please, the Flannery edition and not the Abbott edition).