Kathleen Duey is currently working on the third book in the trilogy.
The lord of Duirs fall. Sadly this book comes out next year I just know the author.
The 20th book in the Magic Tree House series is Dingoes at Dinnertime.
The Third book in the Ingo series is called 'The Deep'.
The third book in the Leviathan series is called Goliath.
The third book in Cynthia Hand's Unearthly series is Boundless.
The third book in the series is called A FAREWELL TO CHARMS
The third book in Alyson Noel's Immortals series is called Shadowland.
The third book of the Dormia series is called: The Shadow Tree.
Book #41 of the Magic Tree House series is called "Moonlight on the Magic Flute" and is scheduled for release on March 24, 2009.
Chains of Reaction is the name of the third book in the Perfect Chemistry series.
No, the third book in the series is called Spell Bound.
The third book in the series is called Small Steps.