Historia animalium ("History of the Animals"), published in Zurich in 1551–1558 and 1587, is an encyclopedic "inventory of renaissance zoology" by Conrad Gessner (1516–1565). Gessner was a medical doctor and professor at the Carolinum in Zürich, the precursor of the University of Zurich. The Historia animalium, after Aristotle's work of the same name, is the first modern zoological work that attempts to describe all the animals known, and the first bibliography of natural history writings. The five volumes of natural history of animals cover more than 4500 pages.[1] The animals are presented in alphabetical order, marking the change from Middle Ages encyclopedias, or "mirrors" to a modern view of a consultation work.[2][page needed]