In 1979, a conference on x-ray microscopy was organized by the New York Academy of Sciences, and in 1983, the Second Interna­ tional Symposium on X-ray Imaging was organized by the Akademie der Wissenschaften in Gottingen, Federal Republic of Germany. This volume contains the contributions to the symposium "X-ray Microscopy '86", held in Taipei, Taiwan, the Republic of China in August 1986. This is the first volume which intends to provide up-to­ date information on x-ray imaging to biologists, therefore, emphasis was given to specimen preparation techniques and image interpreta­ tion. Specimen preparation represents a major part of every microscopy work, therefore, it should be strongly emphasized in this emerging field of x-ray microscopy. Theoretically, x-ray microscopy offers the potential for the study of unfixed, hydrated biological ma­ terials. Since very few biological system can be directly observed without specimen preparation, we would like to emphasize that new information on biological specimens can only be obtained if the speci­ men is properly prepared. In the past decade, many of the published x-ray images were obtained from poorly prepared biological speci­ mens, mainly air-dried materials. Therefore, one of the goals of this conference is to bring the importance of specimen preparation to the attention of x-ray microscopy community. X-ray microscopy can be subdivided into several major areas. They are the classic x-ray projection microscope, x-ray contact imag­ ing (microradiography) and the more recent x-ray scanning micro­ scope, x-ray photoelectron microscope and x-ray imaging microscope.