A long time ago, I read Mary Stewart's Merlin Trilogy, which consists of three books: The Crystal Cave, The Hollow Hills, and The Last Enchantment. I had last read the trilogy back in the mid-1980s, back when I was in high school. So, recently I turned back to these old favorites, and found myself enjoying the tale once again.
Here's a brief background of the story, without spoiling it too much for potential readers. England is suffering under fractured leadership following the departure of the Romans, some time before. England is broken up into several small kingdoms, with a High King to hold them all together, and to try to repell the Saxon threat already encamped on the shores. Into this time, Merlin is born, the bastard child of a local princess. The trilogy tells the tale of his life.
In the first book, Merlin is first a small boy in Wales, where he finds his tutor in magic and the gods and medicine, and is touched by the prophecy which will shape his whole life's work. He flees Wales, for his own protection, and his subsequent actions inexorably lead to the conception of a child: Arthur, the future High King.
In the second book, Merlin is charged by both the High King, Uthur, and his god to keep Arthur in his care, and to train him for his coming challenges. The story closes with Arthur assuming the mantle of leadership, following the passing of Uthur.
In the third book, Arthur and Merlin work to end the Saxon threat, found Camelot, and close with Merlin's final destiny, as he had long since foreseen...almost.
The tale is told in the first person: Merlin. In this fashion, the story feels personal in a way that few other Arthurian fantasies ever have. Merlin, the character, is a sympathetic one: he has good in his heart, he looks after his mission in life with care and humility, and he certainly doesn't buy into this "Merlin the Enchanter" crap circulating about England...though he's not above using it to his benefit from time to time. The other characters in the story are also fleshed out with care...and the characters are certainly not one-dimensional or static.
The storyline is clearly grounded in historical "facts", as much as possible. Clearly Mary Stewart put some time into research, before beginning the writing of this tale.
The writing style is very descriptive. In some novels, the description is somewhat threadbare, willing the reader to fill in the look of the setting to some extent with their own imagination. It's a perfectly valid writing style, and I've enjoyed many books written with that style. Here, however, Mary Stewart has sought to ground us, again, in a historical setting, and she puts a lot of attention into describing the setting so as to help with that grounding process. It's very effective.
So, with the close of the tale, I feel somewhat saddened. Merlin became like a friend. So, I encourage other readers to pick up the challenge, and read the Merlin Trilogy, so you can be touched in this way also.