This book provides a clear introduction to the theoretical issues that ground any in-depth study of the documentary. It explores the legitimacy of the distinction between fiction and non-fiction. It examines the uses of moving images and recording sounds in communication. It describes the implications of various stylistic and structural choices available to filmmakers. The book also covers broad philosophical issues, such as the nature and functions of objectivity, reflexivity, and truth-telling. It embraces a critical realist perspective, and thus offers an alternative to post-modernist and post-structuralist theories of the documentary.
I don't think I can overstate just how great this book is for those interested in documentary films and even the field of film studies as a whole. While ostensibly about nonfiction films and documentaries, the complete book is as much about the rhetoric and representation of film in general, and so serves as a useful primer for a wide variety of cinema studies-related topics.
One interesting thing to note about the book is that it takes the "rhetoric" in its title very seriously, which makes it a bit of an oddity as far as film studies books go. It really does read in some parts more like a book to emerge from a communication or rhetoric program than an explicitly film-focused program, which made it particularly useful and interesting for me.