Rome: The Emperor's Spy is a hard book to categorise. Part thriller, part action adventure, part religious diatribe, I finally put it down as a good read that will be too controversial for some, too complex for others, while some will thoroughly enjoy it.
Read purely as an entertainment, I found the book to be pretty good. The characters have their own personalities and motivations, pantera (the main character) is particularly well drawn and the Emperor Nero gets a better take than the normally Byron-esque version we see - 'mad, bad and dangerous to know'. Of course, as soon as you hear Nero, you think of Rome burning, and that is indeed the climax to this book - not giving anything away there, as this is plainly going to be the ending from very early on. It's not the fire itself that is the real thrust of this book though, but the way in which the characters are brought to it in spite of their efforts to stop it happening or make it happen. This is where the main villain, Saulos, comes in. The leader of a Christian sect who need Rome to burn to fulfill a prophecy, Saulos is better known to us as St Paul, and this is where some people will find their tastes challenged.
If you're terribly religious, I wouldn't recommend this book - St Paul isn't the pnly problem you're going to have. For anyone else who likes a complicated plot, good characters and a book that grips like a free climber going up a sheer rock face, you could do a heck of a lot worse than spending your hard-earned dinarii on this.