This book aims at providing an updated overview on the most frequent pathogens responsible for Porcine Respiratory Disease Complex (PRDC), viruses and bacteria, acting in association and mainly potentiating their anatomical and functional effects and worsening the clinical outcome and economic impact. The authors, prestigious and rewarded experts with a wide experience in respiratory diseases in pigs, have focused their efforts on preparing chapters that illustrate the latest information and data on the treated topics, while making them as readable as possible. The book inspires to facilitate comprehension and educational enrichment to the preparation of a well-designed, practical approach.