This demonstration showcases the STEP system for natural language access to relational databases. In STEP an administrator authors a highly structured semantic grammar through coupling phrasal patterns to elementary expressions within a decidable fragment of tuple relational calculus. The resulting phrasal lexicon serves as a bi-directional grammar, enabling the generation of natural language from tuple relational calculus and the inverse parsing of natural language to tuple calculus. This ability to both understand and generate natural language enables STEP to engage the user in clarification dialogs when the parse of their query is of questionable quality. The STEP system is nearing completion and will soon be field tested in several domains.