THE ONE TREE is in many ways Donaldson's most richly complex book from a psychological standpoint, up to this point in the series. THE WOUNDED LAND dealt primarily with the visceral shock Covenant experiences upon returning to said land and the physical reactions of Linden Avery. We met some new characters and marveled at the changes in the land. And that was enough.
In THE ONE TREE, the relationship between Covenant & Avery grows ever more complex at every turn. They push & pull at each other, struggling with urgent need and vastly divergent understandings of where their quest should take them. We also get to revisit the wonderful giants, briefly reintroduced at the end of THE WOUNDED LAND. In the previous trilogy, we had come to know and love Saltheart Foamfollower, probably the single greatest character ever created for a "quest" fantasy story. While the giants in THE ONE TREE are wonderfully rich and alive, they don't quite reach Foamfollower's status in our hearts. BUT, we get to understand their race more clearly and experience their unbelievable strength and character.
I don't want to rehash the plot...it's been done well enough previously. Some reviewers have complained that the book is too episodic, or that some of the events that take place are just there to fill out the book to proper length. To my mind, the hardships the characters endure serve to illustrate their strength of character and the parts of their psyches that are conflicted or downright torn. I love that. Also, some mention that Covenant isn't the focus of the book as much as Linden Avery...that's okay with me. Covenant, in many ways, is less interesting than most of the other characters. He has my sympathy and support, but he's not the REASON I love these books.
Donaldson makes some remarkable leaps of imagination, and the Bloodguard are very richly portrayed. As readers of past Covenant books know, Donaldson is often very ambiguous about good vs. evil. Yes, Lord Foul is the bad guy, no question about that. But it's the bad impulses in otherwise "heroic" characters that make the books so complex. If you like that element of these books, then you'll love THE ONE TREE. It's full of conflict within the "good" guys.
Many middle books in trilogies have the problem of dangling a little at both ends. They're picking up from a thread of the first book and leaving one behind for the final book. THE ONE TREE has some of that, but the intensity of the final scenes and the resolution of some of the characters is richly satisfying, so rather than feeling let down at the end, you just want to immediately grab the next book. And thank goodness you can...unlike Donaldson's current Covenant books, which are planned to have three year gaps in between.
So, if you've like the Covenant books up until now, you'll love THE ONE TREE. It's more action-packed than THE WOUNDED LAND and more rewarding. If you haven't enjoyed the books (but for some strange reason have read up to this point), your mind won't be changed. And obviously, if you haven't read them but would like to, you MUST go back to the beginning. Do not hope to start reading at this point and just "pick it up as you go along." You'll completely miss 95% of what's going on.