Neutrophils are the most abundant type of white blood cells in mammals and form an essential part of the innate immune system. However, during the beginning (acute) phase of inflammation, particularly as a result of bacterial infection and some cancers, neutrophils are one of first-responders of inflammatory cells to migrate toward the site of inflammation, firstly through the blood vessels, then through interstitial tissue, following chemical signals in a process called chemotaxis. This book presents topical data on neutrophils including neutrophils as biological age markers and predictors of longevity; the role of neutrophils in acute myocardial infarction, Behcet's Disease, bladder cancer, tuberculosis and others.