Motifs in the James Bond film series the degree to which Bond girls are pivotal to propelling the plot forward varies from one film to the next. Five of the Bond girls are "bad" girls (or at least working for the villain) who turn "good" (or switch sides) usually due to Bond's influence. Bond has fallen in love with only Tracy di Vicenzo in "On Her Majesty's Secret Service" and Vesper Lynd in "Casino Royale", but both of them die at or near the end of the respective films. Roald Dahl, a screenwriter of "You Only Live Twice", said he was given a formula to work to
Bond girl the following criteria are used for determining inclusion: women with whom sexual encounters are implied; the woman who principally assists Bond; femme fatales are taken to be women who attempt to kill Bond; sacrificial lambs are taken to be women with an allegiance to Bond whose death is instigated by the main villain or his henchmen. In addition to the Eon Productions films, there have been two Bond films produced by independent studios and one television production. In 2002 former Bond girl Maryam d'Abo co-wrote the book "Bond Girls Are Forever: The Women of James Bond". This book later became