This book presents cutting-edge research on innovative system interfaces, highlighting both lifecycle development and human-technology interaction, especially in virtual, augmented and mixed reality systems. It describes advanced methodologies and tools for evaluating and improving interface usability, and discusses new models, case studies and good practices. The book addresses the human, hardware, and software factors in the process of developing interfaces for optimizing total system performance, while minimizing costs. It also highlights the forces currently shaping the nature of computing and systems, such as the importance of portability and technologies for reducing power requirements, the need for better assimilation of computation in the environment, and solutions to promote computer and system accessibility for people with special needs. Based on the AHFE 2020 Virtual Conference on Human Factors and Systems Interaction, held on July 16-20, 2020, the book offers a timely survey and a practice-oriented guide for systems interface users and developers alike.