'The Power That Preserves' is the last book in the first 'Chronicles of Thomas Covenant the Unbeliever'. Covenant returns to the land after a few days in the real world where is health and state of mind have deteriorated considerably. When he returns to the Land he finds that seven years have passed and the Land is in dire straits as Lord Foul has besieged the Lords at Revelstone and the Land is permanently in winter.
This is the best of the first trilogy as the various threads are brought together and concluded. As well Covenant has lost almost all his bitterness and has come to terms with the land even if he still does not believe its reality. The parallels between Covenant's health and the well being of the land is most explicit in this book- Lord Foul is the leprosy of the Land and if Covenant can 'cure' the land then Covenant can if not cure his own leprosy at least come to terms with it. A good conclusion to an excellent series, but it would get even better with the second chronicles.