A group of nuclear receptor proteins that function as transcription factors regulating the expression of genes are termed as peroxisome proliferator activated receptors (PPARs). They are also responsible for regulating cellular differentiation, development, tumorigenesis in higher organisms. Peroxisome proliferator activated receptors also regulate fatty acid storage and glucose metabolism. The three types of peroxisome proliferator activated receptors which have been identified are alpha, beta/delta and gamma. PPAR alpha and PPAR gamma are molecular targets of a number of marketed drugs, called PPAR agonists. These drugs are used to treat the symptoms of the metabolic syndrome, mostly for lowering blood sugar and triglycerides. This book includes some of the vital pieces of work being conducted across the world, on various topics related to peroxisome proliferator activated receptors. It aims to shed light on some of the unexplored aspects of these nuclear receptor proteins. The book will serve as a reference to a broad spectrum of readers.