The paramount importance of the hologram recording process has been recognized since the pioneering work of Gabor (Ref. 1). It is evident that information lost in the recording step of holography cannot be recovered subsequently. Therefore, it is essential to carry out this step in an optimum manner, retaining as much of the original object information as possible. Since its critical na-ture was widely appreciated, it is not surprising that the effects of this recording process have been the subject of well over one hundred published papers, innumerable talks, and much unreported research. As a result of this substantial effort, many aspects of hologram recording materials and practices are now well understood. However, there remain numerous questions, a few of which will become evident in the course of this paper.