This is the first of three volumes in the "Ion Channels & Transporters in Tumor Biology" collection, which discusses the function of ion transport proteins in cellular and systemic homeostasis. The authors highlight the role of the so-called transportome, which is defined by the entirety of ion transporters and ion channels. Thereby, readers will get a better understanding of the impact dysregulated ion transport has on the whole spectrum of cancer types. Cancers display deficiencies in several, sometimes interdependent members of the transportome. Clinicians will be interested in the fact that controlled expression of ion transport proteins dramatically impacts the life span of cancer patients, as shown in recent studies. These observations offer a promising outlook for biomedical scientists, as members of the transportome could be the tumor markers of tomorrow - both for diagnostic and therapeutic purposes. As part of a three-volume collection, this book will fascinate members of the active research community, as well as clinicians from the cancer field.