An improved version of Rösslin’s Swangern frawen. This contains the first true anatomical pictures in an obstetrics book. Rueff described smooth-edged forceps for delivery of a live baby, preceding Chamberlen, and a toothed forceps for extraction of the dead fetus. He developed a method of cephalic version combining internal and external manipulation. A Latin translation of his book, De conceptu et generatione hominis, was published by Froschauer in the same year. English translation, London, 1637.

The illustrations show contemporary ideas about mammalian embryology.