Sterecon is a software system developed at the BMIRR for interactive tracing and measurement of structures in microscopy images of every type, with the special feature of tracing in 3-D using stereoscopic viewing. A full description of Sterecon was published in J. Structural Biol. 11693-98 (1996), in which the system is offered for distribution. The homepage is www.wadsworth.org/spider_doc/sterecon/sterecon.html with a summary at www.wadsworth.org/spider_doc/bmirr/3-D.html. At the BMIRR, Sterecon is used for analysis of stereopairs from HVEM or IVEM thick sections and also for analysis of confocal z-series volumes. It's major use is for segmentation of nearly every electron tomographic volume made at the BMIRR, as the first step in making striking illustrations and animation's using Sterecon's interfaces to SGI Explorer and SceneViewer for surface rendering. A new version of Sterecon is has been in Open GL instead of Irix GL. It has a more modern user interface for display of reconstructions. We are already routinely using portions of the new version in order to completely debug it. The use of Open GL means that it will be possible to port this new version to the PC, and we propose to start this next year. We are driven to do this since it is clear that the PC will soon become the only choice of imaging platform for most labs. For this, we will need a PC with excellent graphics, compilers, and porting software, an added expense of $5000. Because of heavy use of the system, we continue to use our very first hardware, and an older version of the program, in addition to the SGI system, and still hope to obtain a larger room to make it more comfortable for simultaneous users. So far, the labs of three collaborators, Robert Summers of U. Buffalo, Stanley Erlandsen of U. MN., and Andres Kriete of U. Giessen, Germany have received the syst em. The software has also been distributed to the lab of M. Kirk of Argonne National Laboratory, and to Ted Uyeno of U. of Calgary. We have had inquiries from Terry Gruijters of U. Auckland, NZ, and also from several labs who want to wait until it is available on the PC. The Edge company, manufacturers of a stereoscopic 3-D LM system, has expressed interest in a possible marketing arrangement in association with their microscope, and we have been doing tests with their images.