This detailed survey of present-day scientific communication theory rejects the outmoded "levels" organizational scheme in favor of a system based on the underlying model and fundamental explanatory principle each theory presupposes. In doing so it shows the fundamental similarities among all communication-relevant contexts. Most theories included in the book are causal in nature, derived from one of three underlying models: message production, message reception, or interactive. A few theories take on a functional form, sometimes in dialectic or systemic versions. An introductory chapter describes what is meant by scientific explanation, how that concept is instantiated in scientific communication theory, and delineates the three causal models prevalent in these theories. A useful resource for scholars, this book is suitable for graduate and advanced undergraduate courses in communication theory.