How funny, I’m about a third of the way into Purgatory Explained by the Lives and Legends of the Saints. As to how much you wish to believe from the private revelations provided in the book, the author clearly states that one is free to disbelieve them without sinning against the faith. From the preface:
The teaching of the doctors and theologians, or rather their opinions on several questions relative to Purgatory, and their explanations of them are not imposed as articles of faith; we are free to reject them without ceasing to be Catholic. Nevertheless, it would be imprudent, and even rash, to reject them, and it is the spirit of the church to follow the opinions commonly held by the doctors.
The revelations of the saints, called particular revelations, do not belong to the deposit of faith confided by Jesus Christ to His Church; they are historical facts, based up human testimony. It is permitted to believe them, and piety finds wholesome food in them. We may, however, disbelieve them without sinning against faith; but they are authenticated, and we cannot reject them without offending against reason; because sound reason demands that all men should give assent to truth when it is sufficiently demonstrated.
Having said that, the book does have a Nihil Obstat and Imprimatur.
For myself, I take the revelations at face value. They paint a picture of Purgatory in as great a detail as Dante did, while stating nothing that is contrary to the faith. The most striking thing for me is the similarities present in the stories. They all place Purgatory in the bowels of the earth. They talk about the fires of Purgatory being the same as the fires of Hell. And, whenever time is mentioned, it’s clear that time in Purgatory passes much more slowly than on Earth.
From chapter 16:
The sick man, having to choose between three days in Purgatory and one year suffering upon earth, did not hesitate, but took the three days in Purgatory. After the lapse of an hour, his angel went to visit him in his sufferings.
On seeing him, the poor patient complained that he had been left so long in those torments. “And yet,” he added, “you promised that I should remain here but three days.”
"How long," asked the angel, "do you think you have already suffered?"
"At least for several years," he replied, "and I had to suffer but there days."
“Know,” said the angel, “that you have been here only one hour. The intensity of the pain deceives you as to the time; it makes an instant appear a day and an hour years.”
“Alas! then,” said he with a sigh, “I have been very blind and inconsiderate in the choice I have made.”
I am finding this book immensely valuable. Purgatory never seems to be talked about, and when it is, it is sugar-coated–as if the only sufferings we’ll face is the loss of the Beautific Vision. The revelations do indicate that this pain is greater than the pain of the fires, but they also say that the physical pain of the fires is greater than any faced on Earth.
It’s a tragedy that Purgatory is so downplayed and even believed by so few, when it’s clear the vast majority of us is going to spend a lot of time there. The book has helped me to look at my life in a new light. When I think of how every minor transgression is going to be painfully purged from my soul, I tend to think twice before committing even the most venial sins. I highly recommend this book, though it is difficult to find. Tan Books publishes it.
Peace and God bless! :)
P.S. Oh, be sure to check out the Appendix, which discusses how to receive a plenary indulgence. The book talks about a storehouse of treasures set aside for the faithful to use to avoid the cleansings of Purgatory and that it would be the ultimate shame for these treasures to go to waste.