The third book in Cynthia Hand's Unearthly series is Boundless.
There is no information available about a new book in the Unearthly series by Cynthia Hand being released at this time. The last book in the series, Boundless, was published in 2013. It's unclear if the author has plans to continue the series in the future.
Yes! Unearthly is the first book of a series, with at least 3, probably 4 books total. Each book is scheduled to be released in January, so Book 2 (hallowed) will be out in January 2012, Book 3 January 2013.
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