The first purpose of this study was to identify procedural and heuristic knowledge used when creating web-based instruction. The second purpose of this study was to develop suggestions for improving the Heuristic Task Analysis process, a technique for eliciting, analyzing, and representing expertise in cognitively complex tasks. Three expert web-based instruction designers were identified and selected for interviews based on visibility, recommendations, knowledge, and availability. Each expert was asked to choose three web-based instruction cases and verbalize the steps, underlying thoughts, and guidelines used to create the instruction. The primary procedural steps identified include topic definition, task and content analysis, establishment of web-based instruction objectives, development of the instruction, and elicitation of feedback. The identified heuristic knowledge was mostly exclusive and reflected the contextual and personal history that helped to establish each expert's knowledge. The Heuristic Task Analysis process was instantiated multiple times which provided ample data for process improvement suggestions. The study findings were used to create a theory for web-based instruction and an updated version of the Heuristic Task Analysis. The web-based instruction theory includes six phases that contain the procedural and heuristic knowledge used by expert designers of web-based instruction. The categories of heuristic knowledge identified include instructional design guidelines, content capturing guidelines, interpersonal guidelines, and high-profile project guidelines. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]