The invention of an instrument called the optical microscope and the new possibilities it offered to observe living material must be considered a major milestone in the advance of our understanding of the mechanisms of life. Huge numbers of important observations have been made using this instrument, but unfortunately it only produces two-dimensional images. The advent of the electron microscope, first the transmission electron microscope (TEM) and then the scanning electron microscope (SEM), then made it possible to observe the three-dimensional structure of specimens literally adding a whole new dimension to our understanding and bringing about a second major milestone in microscopy. With their highly specific architecture and great functional significance, the respiratory apparatus and the airways have received particular attention, and extensive series of investigations with SEM have been done. "To see is to understand," and many lung SEM investigations with different aims have been performed, but "to see again is to understand better," so we offer this collection of scanning electron micrographs, which, along with some familiar aspects, also presents new and unusual images of pulmonary morphology. We have noticed that although most pulmonary structures have already been seen, every time we scan a new specimen, new perspectives, new aspects, and new details emerge. We hope that physicians and scientists looking at these scanning electron micrographs will, just as we did, find new sources of wonder, and will then desire to delve deeper.

Bronchial asthma is a multifactorial disease. Cooperation between pneumologists, physiologists, immunologists, pharmacologist and pediatricians is frequently needed for the complete investigation of an asthma case. This means that a physician in general practice cannot alone assess all the aspects of asthma employing different technigues to manage this disease. This book will provide physicians with a unique source on the principal methods which can be used to analyze individual cases of asthma and a helpful refrence source for better understanding the multiple pathways to the disease.

Gastroesophageal reflux (GER) refers to symptoms and events that result from abnormal regurgitation of gastric contents into the esophagus. GER is a common clinical problem that affects large segments of the general population. The spectrum of problems associated with GER is now known to also involve extra-esophageal sites. Respiratory diseases, in particular bronchial asthma, can be exacerbated by multiple triggers, including GER. The relationship between the occurrence of gastroesophageal disorders and changes in respiratory function has been known for over a century, but the mechanism by which intraesophageal acid regurgitation can produce respiratory symptoms is still debated. The reasons for these concurrent pathological events are also not fully understood. Determining, for instance, whether reflux itself initiates or exacerbates asthma, or whether asthma or its treatment primarily causes GER is a matter of current investigation.

A flood of data indicate the importance and the relevance in both respiratory and extrapulmonary disease of Chlamydia pneumoniae infection today. Antibody prevalence rates in Western countries reach 50% in the adult population and remain high in old age suggesting a high rate of reinfection. Chlamydia pneumoniae can cause upper respiratory tract infections, like pharyngitis and sinusitis as well as bronchitis and more than 10% of community-acquired pneumonia. Recent data suggest a possible association of Chlamydia pneumoniae infection with wheezing and adult-onset asthma. However, the most intriguing hypothesis pertains the possible association between Chlamydia pneumoniae infection and atherosclerosis.