Daisy and Henry Lewis have been married for 20 years in the prolonged post-academic haze that living in Cambridge, Mass., has provided them since graduating from Harvard. As the story opens, the Lewises are set to receive an award for graciously playing host to a string of foreign students at Harvard. (''They had hosted Pakistanis, Turks who arrived right wing and went home radicalized, a Brazilian member of parliament whose shirt was open to the waist even in January, a Malaysian couple who curried vegetables sent both Daisy and Henry to the infirmary'' -- the list is almost endless.) While their guests may embody global cultural exotica, their own lives are a study in boredom. Daisy works in a soup kitchen and does volunteer work, righting the wrongs of the world with all the unconvincing self-assurance of a latter-day Radcliffe Florence Nightingale. Soon after accepting their award, Henry leaves Daisy for a Frenchwoman. Daisy in turn meets a Harvard parasitologist named Truman, while her son, who is of course a Harvard freshman, soon loses his own girlfriend (Truman's daughter) to their latest exchange student, an Italian named Andrea. Medwed's novel is meant to be a study of community and family, of the dissolution and rebuilding of bonds, yet you don't empathize with her characters, who seem to lack vision and will. Their lives are filled with rationalizations, including their desire to help others in their own constrained, safe ways. Throughout the often dreary description of their daily existence, you can't help thinking that if this is all they could do with their Harvard degrees, they probably deserve each other. Hardcover. Like New.