The role of adenosine and adenosine receptors in normal cell physiology and in diseases has been an area of active research over the last several decades. The field has advanced from the use of limited tools to examine receptor signaling and function to the use of various molecular and receptor knockout techniques to examine the details of the expression and functions and regulation of these receptors. This book highlights important milestones in adenosine receptor research and reviews recent findings from experts in different research areas. Several research areas, ranging from cardiovascular, cancer, and central nervous system research are discussed. Several of the chapters describe how understanding the basic cellular mechanisms regulated by adenosine could lead to the development of important therapeutics. The editors, Vickram Ramkumar and Roberto Paes-de-Carvalho, have published extensively on adenosine receptors for more than two decades and are still active in this field of research. It is our hope that this book provides an excellent synopsis of the current status of adenosine receptor research which would be valuable for researchers in the field and as a reference source for clinicians and others interested in this area.