Human-Computer Interaction (HCI) is an interdisciplinary field that has gained recognition as an important field in ergonomics. HCI draws on ideas and theoretical concepts from computer science, psychology, industrial design, and other fields. Human-Computer Interaction is no longer limited to trained software users. Today people interact with various devices such as mobile phones, tablets, and laptops. How can you make such interaction user friendly, even when user proficiency levels vary? This book explores methods for assessing the psychological complexity of computer-based tasks. It also presents methods of qualitative and quantitative analysis of exploratory activity during interaction with a computer.