The Chronicles of Thomas Covenant is a series of ten high fantasy novels written by American author Stephen R. Donaldson. The series began as a trilogy, entitled "The Chronicles of Thomas Covenant, the Unbeliever". This was followed by another trilogy, "The Second Chronicles of Thomas Covenant", and finally a tetralogy, "The Last Chronicles of Thomas Covenant". Using only the above description and what you know about the world, "Donaldson got bored of trilogies and thats why the final four books are a tetralogy" is definitely correct, incorrect, or inconclusive? 