The availability of intense x-rays from synchrotron radiation sources permits the elemental analysis of samples in new ways. An x-ray microprobs using these sources allows the analysis of much smaller samples with greatly improved elemental sensitivity. In addition to the higher x-ray intensity obtained at synchrotron sources, the development of high efficiency x-ray reflectors using multilayer coated optical mirrors permits the achievement of spot sizes of less than 10 μm x 10 μm with enough x-ray intensity to simultaneously measure femtogram quantities of many elements in less than one minute. Since samples to be studied in an x-ray microprobe do not have to be placed in a vacuum, almost any sample can be conveniently analyzed. With an x-ray microprobe it is possible to obtain elemental distributions of elements in one, two or even three dimensions.