City Of Illusions by Ursula K. Le Guin

In a distant future Earth, a man with no memory awakens in a forest and is taken in by a small, isolated community. As he gradually learns about the world around him, he discovers that Earth is under the control of the mysterious and oppressive Shing, who manipulate reality and truth. Driven by a quest to uncover his identity and the truth about the Shing, he embarks on a perilous journey across a fragmented and deceptive landscape. Along the way, he encounters various societies and individuals, each with their own perspectives and secrets, ultimately leading him to confront the nature of illusion and reality in a world where nothing is as it seems.