Clinical Focus Series' Hypersensitivity Pneumonitis opens with a brief historical account, followed by descriptions of epidemiologic, radiologic, immunopathologic, histopathologic, diagnostic, and therapeutic developments. A group of highly respected international authorities have contributed the easy-to-read chapters, enhanced by informative visual images. The thread of clinical discussion that focuses on the basic scientific information runs through the book. The contributing authors have effectively condensed the ever growing field with an appropriate balance of basic science and clinical information of HP.