Contents: Preface; Domingo de Soto: Domingo de Soto and the Iberian roots of Galileo's science; The enigma of Domingo de Soto: Uniformiter difformis and falling bodies in late medieval physics; Domingo de Soto‘s laws of motion: text and context; Late 16th-century Portuguese manuscripts relating to Galileo's early notebooks; Duhem and Koyr n Domingo de Soto; Quantification in 16th-century natural philosophy; The certitude of science in Late Medieval and Renaissance thought; The Early Galileo: Galileo‘s sources: manuscripts or printed works?; Galileo's concept of science: recent manuscript evidence; The dating and significance of Galileo's Pisan manuscripts; Galileo‘s Pisan studies in science and philosophy; Circularity and the Paduan Regressus: from Pietro d'Abano to Galileo Galilei; Galileo's regressive methodology, its prelude and its sequel; Dialectics, experiments, and mathematics in Galileo; Index.