This is a "popular history" executed in a scholarly fashion. Would to God we were better scholars ourselves (or had access to the resources and the time and inclination to research same...) so that we wouldn't have to rely on others for our information. Hislop has done the Christian and Roman Catholic world a great service by delineating the difference between the two.
I highly recomend "The Great Controversy" (subtitle: Between Christ and Satan) by E. G. White as a companion to this title as it contains further documentation and a wider range of study. The G. C. treats on the entire Christian dispensation from the time of Christ's first advent until His second advent, and in that vein contains both history and prophecy; all of which is thoroughly documented with Scriptural references. This book is also rather lengthy, as a work with the scope of this magnitude might well be expected, and its prose is also (like Hislop's) rather archaic, having been penned in the 19th century, but truth is timeless. And it will lead you into a closer association with Him whom to know is life eternal.
Forgive me, but I cannot understand why anyone would be so keen to accept, especially in the prevailing atmosphere of empiricism, that which some other person would purvey without having first investigated the truth for one's self.
For those of you that are ignorant of what Catholicism is, and for you Catholics who are ignorant of what other Christian sects, be they mainstream or fundamentalist, espouse, please, find out for yourselves before making another's prejudices your own.
There is unity in difference, and difference in unity (or: what is the Trinity). Why not try to understand one another, instead of accusing one another? Or are we afraid of finding out that we are ALL children of God?
This book will only offend the well-informed, but the ignorant, looking for something at which to point a finger, will love it. Kind of like "Mein Kampf" and other philosophies of hate.