Around 30 years ago I read a sci-fi novel about a future in which the Earth

had been colonized by 300-foot giant aliens. The remnants of humanity

survived as a kind of vermin, living in cavities in walls of the aliens’

houses, coming out at night to forage for food, getting gassed occasionally

when the exterminator came round. At the end of the book a party of humans

manages to infest one of the aliens’ starships, thereby launching the human

race on a new career as interstellar roaches.

Can anyone tell me the name of this book, please? I am about 70 percent

sure the author was Poul Anderson, but I can’t find it among his works on

Amazon. Reply to [email protected], please, with subject line VERMIN.