Albert the Great is one of only a very few scholastics to comment on the entire collection of Aristotle’s biological works. This text, recovered only at the beginning of the twentieth century and never before translated in its entirety, represents Conrad of Austria’s report on a series of disputed questions that Albert the Great addressed in Cologne ca. 1258. Here, Albert adduces his own views—often criticizing other medieval physicians and natural philosophers—on comparative anatomy, human physiology, sexuality, procreation, and embryology. This translation, based on the critical edition that appeared in the Cologne edition of Albert’s work, helps to explain the title “patron saint of scientists,” bestowed upon Albert by Pope Pius XII.