In November of 1895 Wilhelm C. Rontgen observed fluorescence caused by invisible rays emanating from a discharge tube. This discovery of x rays was not a mere happenstance; Rontgen was a highly skilled experimentalist, well prepared to launch a series of clever experiments and startle the world with the announcement of "a new kind of ray." The practice of medicine was transformed, and the era of modem physics inaugurated. X rays have proven essential to the probing of atomic, molecular, and solid-state structures. X-ray astronomy has revealed some of the most exotic and violent phenomena in the universe, including the black holes. X-ray microscopy provides information complementary to what is; obtainable from optical and electron microscopies. In micro- and nanolithography x rays provide high quality aerial images and simple processing, in part because of an absence of spurious scattering, something that Rontgen himself observed. However, application in ultralarge scale integrated (ULSI) manufacturing is still uncertain for a variety of reasons, primarily because ultraviolet optical-projection lithography continues to satisfy commercial needs. X-ray lithography may find application in areas outside the ULSI industry, for example in optoelectronics, flat-panel displays, and magnetic data storage. It has the intrinsic resolution to reach the practical limits of the lithographic process, around 20 nm. However, to approach this limit diffraction blurring must be avoided by reducing the mask-sample gap below 5 mu m, which may not be acceptable in manufacturing. In this event, and in order to retain the lithographic qualities of 1 nm wavelength radiation, projection with Fresnel zone plate arrays could be employed.