Kindle. Very thin Brunner. His conceit here is entirely busted: apparently a star is going to swing past the Earth in a few hundred years past the 100th millennium and the solution is to dig deeply into the past. Jarringly Brunner also wants a progressive society, one still hungry for something, and yet cannot imagine the production of new knowledge. He's all too ready to focus on new sources of addiction, all of which lead to decadence.
Goodreads tells me this later got expanded into Catch A Falling Star.