But somewhere along the line , my resolve weakened and I cracked open Penelope Fitzgerald 's '' The Bookshop , '' which I had already read six years ago ; Paul Fussell 's '' Wartime , '' a gift from my college English professor ; the peerless Tom McGuane 's '' Ninety-Two in the Shade '' ; Henning Mankell 's unnerving mystery '' Before the Frost '' ; and a book about the 1954 French catastrophe at Dien Bien Phu , lent to me by a friend who served in Vietnam .