Brisingr author Christopher Paolini lives in Montana, “with an incredible view of the Beartooth Mountains. Couldn’t ask for a better source of inspiration.”

Random House / Perry Hagopian

Brisingr, by Christopher Paolini, read by Gerard Doyle. Unabridged, 29½ hours, including an interview with Paolini. Listening Library, $60.

By the time you reach the third book of what’s been marketed as a trilogy, you might reasonably expect the story to be ending. Mad king overthrown, youthful hero ascendant, all wrapped up in time for dinner.

But you notice something odd as you near the end of Brisingr, the third book in the saga of teenage dragon-rider Eragon and his dragon, Saphira. The pair and their band of rebels, the Varden, are still traipsing across the land of Alagaësia, fighting minor skirmishes and nowhere near the wicked king’s capital; the tyrannical sovereign lurks far offstage. And you realize that there’s just no way this “trilogy” is ending with its third book.

Still, it’s hard to complain when a book is as full of adventure and derring-do as Brisingr, the best-written so far of what is now billed as a four-book cycle.

The book opens with Eragon and his cousin, the immensely strong hammer-wielding Roran, lying in wait outside the dark castle Helgrind. Inside the castle, the creepy, vicious winged Ra’zac have imprisoned Roran’s kidnapped true love, Katrina.

And right there you have a mini-version of the whole Eragon saga: good repeatedly facing off against evil; humans and super-humans, along with their magical allies, battling ever-nastier magical creatures. Plus lots of oddball names — the book’s title is the word for fire in Alagaësia’s “Ancient Language” — with the occasional normal human monicker thrown in.

Doyle, who reads with a delightful variety of accents and voices — including appropriately grating tones for Saphira and another dragon — seems to take great pleasure in pronouncing all the strange characters, places and incantations. It’s a winning combination that only begins to pall when Paolini slows the action, most egregiously for a lengthy, tedious segment on the inner politics of the Varden’s dwarf allies.

In the interview that follows, Paolini tells how, despite his effort to outline his story beforehand, his characters sometimes refused to obey him. One detour alone forced him to add 100 pages to the manuscript, he says, and resulted in the need to split the final book in two.

In the same interview, his cheery editor discloses that she took a red pencil to the sequence on election of the new dwarf king, though I’d say she didn’t cut nearly enough. Certainly Paolini takes the discussion with good grace, emerging from the half-CD chat as the kind of pleasant personality you can’t help but like.

And ultimately, these lapses are easily forgiven. Paolini, who began writing this best-selling saga as a 15-year-old, turned just 25 this month. No wonder he’s still growing as a writer, something to look forward to as he embarks on the fourth (and last?) book of his four-volume tale.

Alan Rosenberg is a Journal editor.