The Third International Conference on Synthetic Microstructures in Biological Research (SMIBR) was held in Williamsburg, Virginia, September 9-12, 1991. This book represents the compilation of many of the papers and posters presented at the meeting. Publications resulting from previous SMIBR meetings held at Airlie House, Airlie, Virginia (March 24-26, 1986 and March 20-23, 1988) can be obtained from the Institute of Electrical and Electronic Engineers, Inc. (IEEE) Service Center (908 562-5418). The purpose of these conferences is to provide an interface between the engineering community and those at the cutting edge of biological and related material science. The overriding motive for assembling representatives from these diverse disciplines is clear. Engineers, even in 1986, could manipulate materials over dimensional scales on the order of those critical to biological systems. The devices that emerge from these manipulations could then be tailored to monitor system function more directly with significantly more localization than ever before. Thus, one important goal of the meetings is to provide the detailed specifications required for effective interfacing of devices with biological systems under investiga tion.