Multi-user computer-aided design (CAD) is an emerging technology that promises to facilitate collaboration, enhance product quality, and reduce product development lead times by allowing multiple engineers to work on the same design at the same time. The BYU site of the NSF Center for e-Design has developed advanced multi-user CAD prototypes that have demonstrated the feasibility and value of this technology. Despite the possibilities that this software opens up for enhanced collaboration, there are now a new variety of challenges and opportunities to understand and address. For multi-user CAD to be used effectively in a modern engineering environment, it is necessary to understand and address both human and technical collaboration challenges. The purpose of this dissertation is to understand and address these challenges. Two studies were performed to better understand the human side of engineering collaboration: (1) engineers from multiple companies were interviewed to assess the collaboration challenges they experience, and (2) players of the multi-player game Minecraft were surveyed and studied to understand how a multi-user environment affects design collaboration. Methods were also developed to address two important technical challenges in multi-user CAD: (1) a method for detecting undo conflicts, and (2) additional methods for administering data access. This research addresses some of the important human and technical collaboration challenges in multi-user CAD. It enhances our understanding of collaboration challenges in engineering industry and how multi-user CAD will help address some of those challenges. It also enhances our understanding of how a multi-user design environment will affect design collaboration. The method developed for detecting conflicts that occur during local undo in multi-user CAD can be used to block conflicts from occurring and provide the user with some information about the cause of the conflict so they can collaborate to resolve it. The methods developed for administering data access in multi-user CAD will help protect against unauthorized access to sensitive data.