Calvin Trillin begins his wise and charming ruminations on family by stating the sum total of his child-rearing advice: "Try to get one that doesn't spit up. Otherwise, you're on your own." Suspicious of any child-rearing theories beyond "Your children are either the center of your life or they're not," Trillin has clearly reveled in the role of family man. Acknowledging the special perils to the privacy of people living with a writer who occasionally remarks, "I hope you're not under the impression that what you just said was off the record," Trillin deals with the subject of family in a way that is loving, honest, and wildly funny in