One of the prerequisites for survival is the ability of cells to maintain their volume. Thus, during the course of evolution cells have "learned" a variety of strategies to achieve volume homeostasis. This volume regulatory machinery involves regulation of both, cellular metabolism and cellular transport and is exploited by hormones and transmitters to regulate cellularfunction. This book to illustrates the complex interplay of cell volume regulatory mechanisms and cellular function in a variety of tissues. However, our knowledge is still far from being conclusive, and the present collection of reviews is thought to foster further experimental efforts to unravel the role of cell volume in the integrated function of cells.