Our goal is to produce a powerful inference system capable of dealing with a large number of KB rules, and conjectures with diverse features. To achieve this goal, we have built KITP-93 with a logical framework that allows convenient user interaction and easy incorporation of existing inference techniques. We have developed a management mechanism for supporting controlled use of KB rules, high-level user interaction, and incremental development of proofs. We have designed an inference engine by incorporating a variety of efficient inference techniques, and emphasizing the role of term-rewriting, goal-oriented deduction, and decision procedures, as well as interactive proof utilities. KITP-93 has been incorporated as an inference server by a number of formal environments. Significantly, it has been used successfully by a large industrial user in the control flow analysis of Ada procedures. A review of the use of KITP in solving real world problems is included in [2]. Besides proving theorems, other inference services that KITP-93 provides include disproving a non-theorem, simplifying program fragments, and deducing antecedents.