"The High King (The Chronicles of Prydain)" by Lloyd Alexander. Fifth an final book in the series.
When we last saw our heroes, Taran and Gurgi were finally returning to Caer Dallben after more than a year of Taran "finding himself" in the classic sense of the term. At last they are coming home, and to their delight everyone has turned out for their arrival. Unfortunately the joy is not for long. Prince Gwydion has been grievously hurt on his way to the party and his sword of Dyrnwyn has been stolen. Needless to say, this is very bad news. Soon the armies of Arawn-Death-Lord are marching and the time for an end to his reign is at hand. With Taran now a wiser steadier fellow, our band of ragamuffin heroes sets off once more towards adventures, traps, and triumphs. Old friends are met, new friends are found, and many good stout-hearted people die. Still, through it all our heroes never give up and the book is a stirring testament to the will of the average joe. By the end of the book Taran must face his greatest decision yet. And, as author Lloyd Alexander points out, "whether the ending is happy, heartbreaking, or both, readers must decide for themselves".
Out of all the Prydain books, this is the one that bears the most similarity to the aforementioned "Lord of the Rings". This is based on a variety of different factors. The types of battles waged. The evil lord's landscaping. The idea that the bad guy has gotten an object of particular power and can now wield it for evil. Even the ending is similar (though Taran makes a surprise decision that is the direct opposite of Frodo's own surprise decision). Don't feel that this book is a weak knock off of Tolkien's (admittedly) better written baby though. Alexander's at the top of his game here, posing as many philosophical queries as he does political jabs. The presentation of a former good guy who believes peace can only come by joining up with bad guys... heck we're talking WWII political theory here. On top of that Taran is at his wisest in this book. He's poised and confident without being cocky. There's the odd inclusion of a terribly annoying fellow named Glew in this book who serves only to create important plot points and a form of weak comic relief, but fortunately he is the sole flaw of the book. I was greatly relieved too. After the meanderings of Alexander's far weaker, "Taran Wanderer", I was worried that, "The High King" might bog down into dreary who-am-I? type speechifying. Fortunately Eilonwy is present and accounted for in this novel. She fights and gets captured, but at least she's a gutsy ball of gung-ho goodness. As the sole female of the novel she's a welcome relief to everyone's serious even toned conversations. Once again, Eilonwy saves the novel.
"The High King" is far longer than its predecessors, but that's fitting since it's the last in the series. Alexander keeps the action constant and upbeat. I doubt you'll find any serious objections to it. It is sad to say goodbye to the characters we've all grown to know so well in the books. I've always had a serious crush on Fflewddur Fflam so I think I'll miss him most of all. Fortunately there's always "The Foundling" and "Coll and His White Pig" to read for fun. They're not officially part of the Prydain canon but they belong squarely in that world. Consider checking them out if you fall into Lloyd Alexander withdrawal. "The High King" is rightfully considered the strongest book in its series. I recommend it with nary a reservation in sight.