Sally Farber has everything a 40-year-old New Yorker could want: a loving doctor husband; two healthy, adorable daughters; great friends; and a charming book editor who used to be her lover and still calls her Cookie. Sally's fourth book is The History of Happiness, and there's the rub. The deeper she digs, the more elusive a definition of happiness becomes, and the more bedeviled she is by the guilty certainty that she isn't as happy as she should be.