With great quantity comes great chances of a stinker. With Brian Aldiss, and his dozens of novels and one-hundred+ short stories, it was just a matter of time. <DING> It's Cryptozoic (1967). A kitchen sink of fiction, the novel changes identity more times than a Gen Z teen from an ultra-liberal family, making for a difficult piece of fiction to make heads or tails of (mixed metaphors intentional, natch).
Cryptozoic is the story of Bush, an artist living circa 2090. But at the start of the novel he is deep in mind travel in the Jurassic past. Mind travel a form of time travel, it allows people to cast their consciousness deep into the depths of time. Physical contact not possible, people can nevertheless go back and observe, and if they happen to meet other minds, interact. People spend years embedded in mind travel, it's thus happens that Bush has a Rip van Winkle meets George Orwell moment when he awakes. And it's not good.