In this review I assume a certain familiarity with the other two trilogies by Hobb set in the same world. I recommend reading my review of The Liveship Traders Trilogy.

Background

The Tawny Man Trilogy concludes Robin Hobb's writings in the world of the Six Duchies. It consists of three books: Fool's Errand (ISBN 0-00-648601-0), The Golden Fool (ISBN 0-00-648602-9) and Fool's Fate (ISBN 0-00-648603-7). Although the books are published separately I've reviewed them together as the books are not really fit to be read apart from each other.
It's very useful to have read both The Farseer Trilogy and The Liveship Traders Trilogy but it's not necessary for an understanding of the story. However, I heartily recommend reading both trilogies before this one, both on their own merits as excellent fantasy fiction and to fully appreciate the subtle nuances and references in The Tawny Man Trilogy.

After visiting the area round Bingtown and meeting a huge cast, Hobb takes the story back to the bastard FitzChivalry in the Six Duchies. That's right, our favourite assassin from The Farseer Trilogy which we first met in Assassin's Apprentice is our main character once again.
With this change of setting comes a change of perspective. One of the things that made The Liveship Traders Trilogy stand out for me was that Hobb expertly switched perspective from character to character. We were told the thoughts of each character separately which led to deep insights in the motivations of people. The author returns here to a more traditional writing style where everything we sense is told through Fitz. This makes the tale easier to follow but less fresh. Also, if you don't like Fitz you won't like the book. While reading The Liveship Traders Trilogy, if you didn't like a character you just had to finish the chapter to get a change of perspective. There's no easy way out here.

Brief summary

Warning: Spoilers for the trilogy and the two before it follow.

FitzChivalry is a bastard of the Farseer line, the ruling monarchs of the Six Duchies. He thought he left all his obligations behind, along with his loved ones, at the end of The Farseer Trilogy.
Fool's Errand is pretty much about Fitz discovering that he still has ties to the throne and the people around it. He reluctantly agrees to help out on one mission but, before he knows it, finds himself entangled in the intrigue of the court. His prince Dutiful gets ready to marry a princess Elliania of the Outislanders. The Outislanders were enemies of the Duchies for a long time, but for the sake of the Duchies' future Dutiful will marry their princess. As if this isn't enough, Elliania charges Dutiful with slaying the mythical dragon Icefyre which is rumoured to be buried beneath a glacier.

Through this all Fitz tries to find a place for himself and struggles with his convoluted past. A main theme here is that an individual must face the consequences of his past, however much the person thought that that was a closed book.
Another big theme is the way Fitz handles his two magics: the Wit and the Skill. The former is a kind of beast magic while the latter is a more noble but no less dangerous magic. Unfortunately, there's an uprising of mistrust against Wit-users.

Style

Hobb again deftly weaves the different threads into a, dare I say it, epic tale. Most of the loose ends from the previous six books are tied up, most of them in unforeseen ways. The climax occurs about halfway through Fool's Fate and I wondered how she was going to fill the last 350 pages. I needn't have worried, as the second half of the book is fully as engrossing as the 1500+ pages that precede it. Hobb provides a wonderful closure for both The Tawny Man Trilogy as well as the complete Duchies cycle.
Although the books' focus is less exotic than some of the elements in The Liveship Traders Trilogy the books are not necessarily less interesting. By having only one character and less supporting characters, the tale is more personal. Hobb doesn't fall into the trap of making the protagonist a superhuman — he certainly has certain advantages but has more than his share of problems, as well. He errs in many ways, is hurt by people and in turn hurts those he loves, and is often a victim of circumstance. In short, Fitz is a human being, worthy of our attention.
The writing is very good, although certainly not breezy. Another problem is that the story takes quite a while to gather speed. After the first book things progress somewhat more rapid, but some readers may still be put of by the slow and deliberate pace.

Physical presentation

Again, I read the British paperbacks as published by Voyager Books. The covers are done by the excellent John Howe and sport small paintings of objects and people from the stories.
Unfortunately the paperbacks are too flimsy to bear so many pages. After two readings, the books have taken quite a beating.
One more thing: do not read the back cover blurbs, as they contain serious spoilers!

Lessons to learn as a GM

There are several things that I, as a GM, could learn from reading the trilogy. Firstly, combat scenes can be both brief and exciting. Hobb's battles are a fast-paced affair, over before you know it, but they have impact.
The author's slow description of the Outislander culture and the Duchies' reaction to it is fascinating. Fitz and the other Duchies character know that the Outislanders have other customs, but know not in what way they differ or which ones are important and which not. The uncertainty of this is very well played out, without resorting to, as it were, failed Language checks. Related to this is the fact that the Outislanders have a matriarchal culture, something alien to the Duchies and a thing that I haven't seen often in fantasy. The truly different culture was really inspiring.
An issue in the grand scheme is the way that the Wit-users are handled. They are mistrusted by the general populace, and try to carve out their own place. Two things strike me here. First is the way that this distrust is portrayed, which could easily extend to the manner people look at psionics (or any other magic) in another setting. Secondly, the fashion in which the Wit-users react to the oppression is wholly believable.
Closure is also an area in which The Tawny Man Trilogy shines. Not only the trilogy itself is expertly brought to an end, but the whole cycle as well. Hobb is not afraid to take her time tying the various strands up, something that is often difficult in our campaigns.

Conclusion

There's only one reasonable conclusion to all this. If you like low-magic fantasy where characters play a central role, or if you've read any of the previous books in the cycle, read this trilogy. Robin Hobb is on top of her game and provides a gripping tale. Even though the environment is less exotic than in The Liveship Traders and the perspective is once again from only one character, this trilogy delivers.