Authoring tools have evolved over the last decade based on technological and pedagogical innovations, from authoring bounded, program-controlled learning systems such as Computer-Based Instruction (CBI) to authoring unbounded, learner-centered environments such as Web-Based Instruction (WBI). This paper discusses the current state of authoring tools and their pedagogical effect on the development of learning systems. It provides a taxonomy of authoring tools and their underlying paradigms and a detailed table that compares and contrasts pedagogical attributes of CBI and WBI. The paper also discusses tow innovative approaches on how future authoring tools can preserve the level of usability and the instructional methods that instructional designers have become familiar with while allowing more powerful and flexible learning systems to be built. (Contains 36 references.) (Author/AEF)