This handbook brings together 12 chapters written by leading scholars in the field who provide perspectives and syntheses of important issues in speech processing and language learning in Chinese, with particular reference to lexical tones. In this book, the inter-disciplinary nature of the field is reflected in the diverse expertise of authors and the fields that they represent, including linguistics, psychology, cognitive neuroscience, education, and communication disorders. The research designs and methodologies used by researchers in this field are multidimensional, including but not limited to paradigms and methods from humanities, social sciences, computational science, neuroscience, and genetics, as clearly illustrated by the many studies either conducted or reviewed by the authors of this volume. In this introductory chapter, we discuss general issues addressed in different chapters, present the organization of this book, and provide an overview of each chapter. We hope that the readers will take our introduction as a starting point to read the individual chapters and then consider to examine the specific research issues further.