Like, I expect, many people, it was the film of The Black Rose that led me to the book. The movie is, for the most part, quite good, but it definitely feels like a movie of a much longer book. Oh, and the female lead is irritating to the point of ruining every scene she's in. So I was left very curious as to how the original would play out, and then I found a first edition for 6 bucks. Hooray!
All told, The Black Rose is a great book. It's a big and sweeping epic that manages to stay very personal throughout. It succumbs to showing the parts of the "Far East" to which its hero travels as exotic in some senses, but never flinches from portraying the England of the 13th century as backward, barbaric, and cruelly stratified. Costain reserves special vitriol for chivalry itself, which is a refreshing change of pace in a historical romance. (It reminds me of Prince of Foxes.)
What's more, the portrayal of "The East" is, for the most part, especially considering the time in which this was written, quite good. What we see of China itself is portrayed with quite an even hand, neither deifying nor condemning it's people, ways, system of government, or much else. Costain deals a little more harshly with those in-between England and China: the Middle Easterners, the Mongols (sort of), and even the Italians a little bit. Although, even in showing the Mongols as pretty damn scary, he does not hesitate to make it clear that their military might, at that time, would have absolutely flattened Western Europe, if they'd bothered to go that far.
Walter is certainly an interesting protagonist to follow, although what's most interesting is watching him slowly come out of his weird, medieval ideas of class. As in the movie, his relationship with the yeoman Tristram is actually the most interesting interplay in the book. The female lead, Maryam, is, thankfully, much better than in the movie, where she is simply petulant, useless, and irritating. In the novel one can see where that characterization came from, but she comes across much better here--and the greatest undertaking in the final pages is all hers.
Where Costain shines the brightest, however, is simply in his portrayal of time and place. There are so many great passages that I could quote, were they not a page or two themselves, that set the scene and the way of thinking for the period so remarkably well as to be almost uncanny.
There are, however, problems with the book. Most notably, where it comes to race. Costain is quite preoccupied with skin color. Fair enough, for the time in which he was alive, but nonetheless it becomes a little strange. That it's so important that Maryam, the "Eastern" girl who loves Walter is half English, and therefore pale, becomes tiresome and a little weird, at points. And there are definitely some disturbing aspects to the character of Mahmoud, even if he is, all told, quite likable. The constant mentions of Asian characters as "yellow," even when it is not meant as a bad thing, will certainly sit badly with the modern reader as well. There is also a certain distasteful scene involving an English Jew, but all told these are the sort of things one must expect from older books, and it can be overlooked, especially in light of the (slightly) intercultural romance which must have been a big deal for the time, and the fair treatment of many of the non-white characters.
(As a sidenote: I wonder how anyone writing in this genre can be racist and antisemitic when they must all be fans of Dumas and Scott... but whatever.)
The book is also kind of missing a definitive climax, and a certain event near the end of the book doesn't get the kind of pay off that it really should (the most I can say without a spoiler). But, all told, it is a wonderful adventure to sink oneself into for awhile, that ranges all over the known world of the period in which its set. I went around buying most of Costain's other books as I was reading it, so that should tell you something.