The Directory attempts to list all heavier-than-air flying machines, whether models or of man-carrying size, which are said to have been built and tested in western Europe prior to the Montgolfiers. While I do not include machines which are known to have been totally imaginary, I have been fairly liberal in my sifting of the evidence. Thus the list includes items ranging from those about which there is no historical doubt whatever (eg, the ornithopters of Blanchard) to others which may never in fact have existed (eg, the zany structure conceived by d'Alcripe's drunken Norman labourer).