The écorchés that Honoré Fragonard created between 1766 and 1771 have miraculously survived the ravages of time due to a technique of preparation which Fragonard never revealed. The present paper and a subsequent article aim to explain the classical methods used by anatomists of the 18th century (Part 1) and to throw light on the details of Fragonard's method (Part 2). Anatomists of the 18th century who wished to preserve their dissections used a method of mummification, which has now fallen into disuse: drying after immersion in alcohol. This article explains the stages of the classical method utilized by French anatomists of the Age of Enlightenment. The cadaver was selected with care before the vascular system was injected with a colored mixture of wax, animal fat, and plant resins. The body was then dehydrated by immersion in a bath of alcohol, after which it was removed and positioned by means of a wooden framework, which held the body in the desired pose while the alcohol evaporated. The vessels were painted, and finally the body was varnished. Clin. Anat. 23:249–257, 2010. © 2010 Wiley-Liss, Inc.