Abstract : This paper describes our experience in applying a generic Intelligent Tutoring System (ITS) authoring tool to specific training applications. The Internet ITS Authoring Tool (IITSAT) was developed to greatly decrease the time to develop tactical decision-making ITSs and was based on the experience from several previous ITS projects. IITSAT allows ITS authors to organize course principles, articulate teaching methods, specify courseware, and develop a case base of scenarios for students along with a specification of how the student's actions will be evaluated and his mastery of the required knowledge assessed. Every scenario defined in IITSAT must have an existing simulation. Evaluation of the correctness of actions and inference of the student's knowledge may be performed by external code, or with libraries supplied with IITSAT. They support both the use of finite state machines (FSMs) to evaluate a student's actions in a free play simulation, or comparison to correct and likely incorrect solutions for each scenario. There are several different instructional methods to choose from including who should control the sequence of instructional events - the student, the author, or the ITS and what that sequence should be. The FBCB2/Tactical Decision-Making ITS prototype teaches armor company commanders by presenting course material and examples, then testing the commander in tactical situations displayed as FBCB2 overlays or in a commercial tank simulator interfaced to the actual FBCB2 software and the ITS. By using IITSAT this ITS was developed in a small fraction of the time normally required. The FSMs successfully evaluated the student's actions in the free play simulation. IISAT's comparison libraries successfully evaluated a student's battle plan with the addition of domain-specific code. IITSAT's ITS engine could usually be specified to make appropriate instructional decisions.