This is the first public release of the bioisostere program. The primary purpose of this release is to garner feedback concerning the functional aspects of the scientific product. Critical questions to address include; does it work in prospective studies, are users satisfied with the fragment database, are the three types of bioisosteres incomplete, sufficient or overwhelming. This release has a minimal feature list, but should be stable and robust. While it is not exceptionally slow, it has not been optimized for speed nor has it been adapted to PVM or MPI.