This book describes a research study in the field of Human-Computer Interaction (HCI), specifically usability evaluation. The research investigated ways to optimise the usability of Web sites. The study commenced with a literature review regarding the process of usability evaluation of Web sites. Various usability evaluation methods and techniques were explored, and two emerging techniques were chosen for further investigation: a contingent heuristic approach and eye gaze tracking. Two experiments were also conducted to evaluate the usability of Web sites. The first experiment utilised an online questionnaire based on the contingent heuristic approach, and the second experiment involved eye gaze tracking with the faceLAB system, while participants interacted with Web sites of different types. Overall, this book presents the bridging between theoretical and practical facets of usability evaluation, which are equally important. Both academicians and practitioners will benefit from this study, because it emphasises emerging usability evaluation techniques, while it still pays respect to the common aspects of standard usability evaluation.