This multi-media work of Embryologie human A for objective to involve the reader at discovered stages which govern the development of the embryo and the human foetus since the initial phenomenon of fecundation until the birth. This evolution proceeds in two great periods: - the embryogénèse (formation of the embryo) characterized by cellular differentiations which lead to the individualization of fabrics and the formation of the outlines of the bodies (subject covered in this first volume); - the organogenesis (formation of the bodies) characterized by replannings and phenomena of maturation which lead to the constitution of the bodies and the apparatuses (subject which will be treated in the second volume).