I would probably give this book three and a half stars, which is not an option here. I thought it was well-written and had many interesting, memorable scenes, but the book did not really feel like a cohesive whole. The story follows an interracial family in an academic setting. The father is a white art history professor at a private liberal arts college in a fictional suburb of Boston; his wife is a black southern woman and they have three kids.
The title "On Beauty" comes from a poem, which is quoted at one point during the book. The book did comment on different types and perceptions of beauty as well as different kinds of intelligence and intellectual styles. These themes are conveyed through the novel's many characters. For example, there is the wife, Kiki Belsey, a large black woman with beautiful skin who radiates with a goddess-like presence, who notes that people expect this like her as a black woman of her size. She is not in the academic world, but is perhaps the most emotionally intelligent character. Her husband Howard is an average-looking white middle-aged man, who struggles with finishing and publishing his academic scholarship and whose style tends to dispute common understandings about the art world. (His main thesis is that Rembrant wasn't really anything special, he was just painting to fulfill the requests of the clients who commissioned him.) Another professor, Claire Malcom, is a petite, thin white woman who wears no make-up and might seem not to care about her appearance, though it is revealed that she has been ordering salads almost her entire life, practices yoga in order to stay young and flexible, and pays careful attention to her bikini line. Claire is a poet and is somewhat looked down upon within her department for not being a "real" academic. Howard and Kiki's daughter Zora tries too hard in both respects. She spends considerable time getting ready in the morning and pledges at the beginning of the semester to swim everyday and lose weight. She also works inredibly hard in her classes (she is a sophomore at the fictional college, Wellington), but does not seem to have any real opinions of her own. What she lacks in natural beauty or talent, she makes up for with hard work and persistence.
Similar analysis can be made for almost every character, some we barely meet at all. For instance, in the course of three pages we are introduced to a college freshman who was the academic star in her high school who is terrified to open her mouth in Howard's class for fear of saying something stupid. As quickly as she is introduced, she is gone, never to be mentioned again. This breadth of characters provides these various human idiosyncrasies, but in some ways damages the story as a whole, never letting us get to know one character or storyline in depth.