This is a critical edition of the Latin text of Book I of the De Institutione Feminae Christianae of Juan Luis Vives together with facing English translation. The work was written in 1523 and dedicated to Catherine of Aragon for the instruction of her daughter Princess Mary. It was later thoroughly revised and the changes introduced are of great interest for the history of the text. The De Institutione is considered to be the most important treatise of the Renaissance on the education of women, cited and imitated throughout the sixteenth century. Although Vives sometimes betrays traditional attitudes towards the status of women, he gives expression to many liberalizing humanistic ideas. In all, it is a clear public acknowledgment of women's probity, dignity and capability for learning.