Human-Computer interaction refers to the science of developing better interfaces for users (humans) and computers. It includes the elements of media studies, computer sciences, design and behavioral sciences, etc. This area of study is growing at a rapid pace and changing technology as we know it. Human-Computer interaction study is based on human to human interactions and tries to recreate the same design technologies humans use while communicating with others. This book aims to provide deep knowledge about this subject. It makes constant efforts to make the understanding of the difficult concepts as easy and informative as possible, for the readers. This text is an essential guide for both academicians and those who wish to pursue this discipline further.