Brian Aldiss 
Helliconia Summer 

The second novel in the epic Helliconia trilogy. It is the summer of the Great Year on Helliconia. The humans are involved with their own affairs. Their old enemies, the phagors, are comparitively docile at this time of year; yet they can afford to wait, to take advantage of human weakness – and of the king’s weakness. How they do so brings to a climax this powerfully compelling novel, in which the tortuous unwindings of circumstance enmesh royalty and commoners alike, and involve the three Helliconia continents.