This book focusses on the latest results related to the field of  bile acids as signaling molecules  and describes how these receptors have become a major pharmacological target. It covers all major areas of research in this field, from genetics, chemistry, in silico modeling, molecular biology to clinical applications, offering a cross-country view of the functional role of bile acids as signaling molecules, virtually acting on all major areas of metabolism. While FXR  and GPBAR1 are essential bile acid sensors that  integrate the de novo bile acid synthesis with intestinal microbiota and  liver metabolism, in a broader sense,  BARs  play a pathogenic role in the development of common human alignments  including  liver, intestinal and metabolic disorders, such as steatosis (NAFLD) and steato-hepatitis (NASH), diabetes, obesity and atherosclerosis.