Audible now has the unabridged audiobook of The River of Souls available for pre-ordering. The audiobook is scheduled for release on May 31, 2014. The narrator is the great Edoardo Ballerini, who narrated the first four Matthew Corbett audiobooks.
Pre-order The River of Souls audiobook from Audible
Pre-order The River of Souls audiobook from Amazon US
Ordering links for all of the Robert McCammon audiobooks can be found here.