Cetology (the catacean study) has lived alternate vicissitudes in the human history, passing from historical periods in which great (in order then) scientific studies were made, to others in which these animals were ignored often committing rough errors of classification. The first known studious of the cetaceans (from the Latin "cetacea" in its turn from the Greek "keté" marine monster), was Aristotle which, in spite of the scarcity of means of the age (384-322 a.C.), he succeeded to comprise their fundamental characteristics; he classified them like intermediate organisms between land and aquatic animals having in common with the first lung presence and therefore the respiration of the air and with second the lack of limbs and the feeding composed with aquatic animals. He realized therefore the nature of mammals of the cetaceans, characterized from the gestation, from birth of puppies already formed and not through the egg deposition, from the production of lait for breast-feeding, beginning to study their sociality. The naturalists writers who dealt of the cetaceans in the successive centuries, not many moreover, often followed the writings of Aristotle without to add nothing new (Plinio Old the 29 d.C. Naturalis Historia). In the Middle Ages there was'nt any scientific interest for the study of the cetaceans, only in Arabia (with writers like Avicenna) and with Icelandic writing (of 1240 d.C.) "Speculum regale". operates of. With the renaissance the crisis of the classics gave impulse to new studies (P.Belon wrote Histoire naturelle DES éstranges poissons marins and Universae aquatilium Historiae, and G.Rondelet) also supported from dissections of captured animals, but many was the doubts, pack-saddles to think that the cetaceans were still placed between fishes. Other books in which accidentally were spoken about the cetaceans, without moreover to add nothing of new, were the report on new travels and explorations during which such animals were met. Nothing of new came added by the natural history compendiums in wich the authors copied from old writings but sometimes in a very careful way (Buffon in the first half of the ' 700) that did not happen in the case of Cuvier which it began the comparative study of fossils and living animals (publishing its studies in first of the 800). Often the information cited on these treatys did not derive from the directed observation but from storys of the travellers. From the half of the ' 600 in ahead many studies bloomed also on the anatomy of the cetaceans studied for more in occasion of died on beach (Bartholin, J. Ray, And Tyson, To Monro, but above all J. Hunter) or of travels on whale-boats (W. Scoresby). In the '800 there was one true and own outbreak of scientific treatys, monographys and banns on reviews (ex. T. Beale on the techniques of hunting of sperm whale 1835; F. Beddard Book of whales; in United States E.D. Cope and W.H. Dall). The '900 mark the true one carried out in the study of the cetaceans to cause also of one increasing knowledge that much species was already on the hem of extinction (F.W. True, Barret-Hamilton, M.A.C. Hinton); were created study committees in order to verify the risks of the indiscriminate capture (Discovery program). After ' the 45 new oceanographic technologies, the governmental financings, and a felt requirement of protection pushed the cetology to important studies and discoveries (sometimes pushed from the studies in captivity). The modern cetology (whose studies have carried to a size of data, than in small part comes brought back in this site) constitutes carried of 2300 years of observations and studies.