to publish the book De Humani Corporis Fabrica Libri Septem (On the fabric of the human body in seven books), a groundbreaking work of human anatomy he dedicated to Charles V and which many believe was illustrated by Titian's pupil Jan Stephen van Calcar. About the same time he published another version of his great work, entitled De Humani Corporis Fabrica Librorum Epitome (Abridgement of the On the fabric of the human body) more commonly known as the Epitome, with a stronger focus on illustrations than on text, so as to help readers, including medical students, to easily understand his findings. The actual text of the Epitome was an abridged form of his work in the Fabrica, and the organization of the two books was quite varied. He dedicated it to Philip II of Spain, son of the Emperor. The Fabrica emphasized the priority of dissection and what has come to be called the "anatomical" view of the body, seeing human internal functioning as a result of an essentially corporeal structure filled with organs arranged in three-dimensional space. His book contains drawings of several organs on two leaves. This allows for the creation of three-dimensional diagrams by cutting out the organs and pasting them on flayed figures. This was in stark contrast to many of the anatomical models used previously, which had strong Galenic/Aristotelean elements, as well as elements of astrology. Although modern anatomical texts had been published by Mondino and Berenger, much of their work was clouded by reverence for Galen and Arabian doctrines. Besides the first good description of the sphenoid bone, he showed that the sternum consists of three portions and the sacrum of five or six, and described accurately the vestibule in the interior of the temporal bone. He not only verified Estienne's observations on the valves of the hepatic veins, but also described the vena azygos, and discovered the canal which passes in the fetus between the umbilical vein and the vena cava, since named the ductus venosus. He described the omentum and its connections with the stomach, the spleen and the colon; gave the first correct views of the structure of the pylorus; observed the small size of the caecal appendix in man; gave the first good account of the mediastinum and pleura and the fullest description of the anatomy of the brain up to that time. He did not understand the inferior recesses,