This book is based on several decades of authors' research and practical experience in the areas of industrial and commercial buildings ventilation and energy efficiency as well as in process optimization in different types of industrial facilities. The Book discusses different types of air curtains used around the world and describes design, applications, pros and cons and examples for each type of air curtain.  The book is illustrated with schematics of air curtains and pictures from their real-life implementation from around-the -world. To compare various design of air curtains, authors propose several indicators/efficiency criteria, which address effectiveness of air curtains, their energy and performance efficiency.  The target audience for this book are energy and process engineers and designers of large commercial and industrial facilities, warehouses, and hangars.