I want to add my two cents here, as AnastasiaFan and I started to discuss this topic on a different thread.
One of the reasons I liked FOTR is because until this book came out, I always felt like something was missing from the portrayals of the characters in other Romanov- related books. The personalities were often polarized, either too stereotypically good or too stereotypically bad, kind of flat even because of that. The authors always seemed to take sides and go out of their way to show either the angelic IF or the evil revolutionaries. To me, somehow something was always missing in these portrayals, something I couldn't quite put my finger on but I always felt that there must be more to it. In FOTR we saw things that were different. We saw the IF members that were not such an ideal family after all, instead a normal human one with all the issues and problems of a normal family. They had issues like normal teenage daughters have with their mother (who doesn't?). This of course didn't mean they were matricidal, or that they couldn't stand the site of her or would never write loving notes or letters to her, they just mean that there were normal tensions between the mother and her children, as we can witness across the board in a common human experience, royal or not they were human. Somehow the portrayal in FOTR seemed more realistic to me. I know there have been many accounts of the IF being the most harmonious and the most ideal family ever, who never had any discords among each other or any disagreements and who all loved each other at all time and never argued. This is all very nice, and I am sure some people really did see them that way. But we all know that things are rarely, if ever, what they appear to be. I am not saying that this means that things behind the royal doors were totally different than they seemed, or that when no one was looking Nicholas would get drunk and beat his wife and children or something like that, but I am fairly sure that they were not as ideal as they have been described in the past. I am certain that beyond the "facade"(for the lack of better term), they were real human beings - teenagers or young adults, with mood swings and all. I don't think that makes them seem any less admirable in certain ways that they were, and it doesn't make them any less likable. In fact, quite the opposite, it made them seem more real and more interesting. I think this was the first book that actually addressed many of these things, and maybe this is why many people were taken aback by it. But just because something was never addressed in other books before, it doesn't mean at all that it must be false information. In fact, from what I understand, Penny and Greg were two of very few Romanov historians who actually went to primary sources for their references, and this makes it more credible to me.
Helen