When Princeton sophomore F. Scott Fitzgerald met the beautiful, impetuous, wealthy 16-year-old Ginevra King one St. Paul evening in 1915, their attraction was immediate and intense. For two years, they played out their romance in letters he growing in jealousy, she increasingly indifferent which ended shortly after her engagement to another man. Her missives, recently made public by Ginevra's granddaughter, are the treasure of this otherwise slight book, revealing the privileged woman who inspired some of Fitzgerald's most memorable heroines, notably The Great Gatsby's Daisy Buchanan. ''She was the first girl I ever loved and I have faithfully avoided seeing her . . . to keep that illusion perfect,'' he wrote. A fascinating portrait not only of a first love, but of how a writer used the unspoiled memories of youthful idealism and bittersweet emotion to fuel his career.