The main theme of the book Introduction to Communication Sciences is to provide information on (a) communication, language, speech & their components in brief with illustrations, (b) production, characteristics and generation of sound in detail, (c) sound intensity and concept of decibel, (d) hearing mechanism, audibility and hearing, and (e) introduction to the field of speech-language pathology and audiology including historical aspects of these two fields in five chapters. It is primarily written for libraries and with an intention of helping students studying in the first year of the speech and hearing Bachelor's programme, master's students in Speech Pathology, research scholars, and faculty teaching Speech Pathology and Audiology. The book is different from others as it incorporates literature from ancient Sanskrit literature and includes several illustrations for ease of understanding. It incorporates definitions of speech, language, communication, and their components, functions of communication, normal development of speech & language, pre-requisites and factors affecting speech-language development, cultural and linguistic issues in communication; bi/multilingual issues. It addresses overview of speech production, speech mechanism, the acoustic theory of speech production, and bases of speech and language. In addition, the book focuses on acoustic energy and power, absolute and relative units and measurements, Bel and deciBel, sound pressure and decibel sound pressure levels, and characteristics and application of decibels. Hearing mechanism, audibility and hearing is also dealt with along with hearing range, procedures of estimating minimum audible levels, minimum audible pressure and field, reference equivalent threshold sound pressure levels and hearing levels, and other related issues. Finally, it introduces the historical aspects of the field of Speech-Language Pathology and Audiology, development of the field in global context, interdisciplinary nature of the field, development of instrumentation in the field, and scope of practice of the field. As historical aspects are dealt with, material from WWW were included and hence internet references were inevitable. The course is required / hard core / discipline specific core course, and hence the proposed book would be used as a primary text. With its reader-friendly content and valuable online resources, Introduction to Communication Sciences is an ideal text for beginning speech pathology and audiology students and faculty.