This is a third edition of the popular book, which presents an overview of the most recent findings in the biology of neutrophils. These cells are critically important for protection against bacterial and viral infections and have been recently demonstrated to be a major contributor to tumor associated immune suppression. In addition, neutrophils represent a unique model for studying fundamental questions of cellular biochemistry and molecular biology. This monograph provides a detailed description of signal transduction, generation of reactive oxygen, and mechanisms of migration and death of these cells. Besides that, it contains unique information regarding neutrophils role in cancer. Finally, this monograph describes recent advances in attempts to improve neutrophil function and use these cells in the treatment of diseases.