X-ray lithography provides a means of replicating, in a single large-area exposure, submicron linewidth patterns made by scanning electron beam lithography. The technique is complementary to existing electron beam technology, and provides a number of unique advantages: (i) it is simple and inexpensive; (ii) the penetrating character of x-rays makes it relatively insensitive to contamination; (iii) both positive and negative type resists can be used; and (iv) because of the absence of backscattering effects, both positive and negative type patterns can be made with equal facility. Exposure times of seven minutes have been achieved for 3 μ mask-sample gaps. This can be decreased to less than one minute by using a rotating anode, or by reducing the mask-sample gap. The most recent results in x-ray lithography are reported, including the fabrication of surface wave devices. The elements of a multiple-mask alignment system are described. This system should permit the rapid and automatic superposition on a substrate of patterns from several different masks, to a precision of 1/10 μ.