This book describes how the analysis of the trace gases in exhaled breath can be used for non-invasive clinical diagnosis of disease and for monitoring the effectiveness of therapy. This approach offers an important addition to the diagnostic techniques available to medicine, having the advantage that on-line breath analysis can provide information to the clinician immediately and thus facilitate rapid diagnosis and treatment. The book is a compilation of contributions to a conference held in Dornbirn, Austria, 23-26 September 2004 on various aspects of this new topic. Written by the foremost workers in the field, it will provide clinicians and others in the medical fraternity with an up-to-date summary of the status of the subject. The wide scope of the chapters ranges from descriptions of the analytical methods that are available, through the use of breath analysis in the study of physiological phenomena, to the identification of biomarkers of particular injury and disease.The proceedings have been selected for coverage in: