The present book focuses on the capabilities of laser photoacoustic spectroscopy method in high impact and new frontier of modern applications: medical diagnosis based on exhaled breath analysis with special importance on the theory, application of the simultaneous measurements of ethylene and ammonia absorptions and the study of exhaled respiration of subjects with renal failure together with breath test analysis of one prevention domain: smoking. This book consists of 4 chapters plus appendices, the first two chapters are focussed on general introduction to human breath biomarkers and the...