Box 8.1 lists the items you need to make all the holograms described in this chapter. e only limitation on the subject matter (apart from size) is that it has to be mounted on its side; and the subject illumination, as with the Denisyuk congurations, is somewhat basic. e bypass principle in its simplest form was rst described by Hans Bjelkhagen as early as 1977 [1] and was subsequently adapted for holographic interferometry by Nils Abramson [2].