I read several Asimov novels back in the late 70's and two story lines have stuck with me but I cannot recall the titles. They may be from the same title. The first story line is a future setting where people no longer have any personal contact. In fact the thought of being in the same room with another person and breathing in air that was previously in the other persons lungs is sickening. I remember that people lived alone in large mansions and communicated only electronically. Babies were raised far away on farms. The other story line involved time travel. Time travel was accomplished by entering something I believe they called a kettle and it was almost like a lift or elevator. Different times could be visited as one would ride an elevator and visit different floors. This allowed people to live freely in different times and travel between them at will. Anyone recall what books these story lines were contained in? Thank you!