"Oh, good, Watly. Oh, good. Perfect timing. Just perfect. Couldn't've asked for better. Things'll be ready in just - almost perfect timing, Watly. A few more minutes and we'll sit down to a - be ready in a few minutes, Watly. You have a seat and put your feet up."This 1991 novel may have been partly inspired by Frederik Pohl's memorable 1974 story "We Purchased People", with which it shares the concept of human bodies being rented out for use by other intelligences, the original owner helplessly aware as murder is committed by their hands. However it's not quite in the same league - where Pohl's protagonist is repulsive and has done dreadful things with the result that he is punished by being rented out to aliens, Emshwiler's Watly is participating in the free market and renting himself to rich humans, in a near-future surveillance society which is sexually liberated in many ways except that it remains deeply homophobic. The impact is very different - Pohl gets us to sympathise with an awful man to whom awful things happen, Emshwiler switches from the implications of the hosting technology to standard techno-thriller mode once we've had the original setup, allowing him to explore his future city at exciting pace, before the inevitable twist leads to a predictable conclusion.
This was the SF book that had lingered longest unread on my shelves. Next in that list is This Mortal Mountain, Volume 3 of the Collected Stories of Roger Zelazny.