The fourth book of the Power of Three series is called Eclipse.
It is already out and it is called Closer 4th book of the series.
The fourth in the series is called Beautiful Redemption.
The book is called Torn and it is coming out in august of 2011!
The title of the second book of the 4th series of Warriors is called Fading Echoes.
They all have different names. The first series is called the Original Series, the second is called The New Prophecy, and the third The Power of Three. Erin Hunter is coming out with a new series called the Omen of the Stars. There is only one book out yet in that series which is called The Fourth Apprentice. I think you're talking about a series as in trilogy, saga, or quintet. I don't know the name of anything other than that, but I just wanted to clear that up.
Yes, there is a 4th book to C.C. Hunter's Shadow Falls series. It is called Whispers at Moonrise.
Actually the 4th book series is called omen of the stars. The first book in it is called The Fourth Apprintece.-Icemask
You mean Percy Jackson and The Olympian Series? It's called The Battle Of the Labyrinth.
It's called Finale and will be out in the fall, 2012.
The fifth Power of Five book will be released on the 4th October 2012 and will be called Oblivion
the fourth book is called "THE VAN ALEN LEGACY" and it comes out october the 6th
The 4th book is coming out in September 2010, It is called: This isn't what it looks like