Macromolecules which are composed of long chains of amino acid residues are called proteins. Each protein consists of at least one long polypeptide. The sequence of gene that is encoded in the genetic code is responsible for defining the sequence of amino acids in a protein. The lifespan of protein is measured in half-life, and can range from minutes to years. Protein science is a branch of biology which attempts to develop an understanding about the role of proteins in genetics, evolution, and molecular and cell biology. It also focuses on the structure and functions of different types of proteins. This discipline employs various techniques such as protein purification, structure determination, cellular localization and chemical analysis. This book explores all the important aspects of protein science in the present day scenario. It aims to shed light on some of the unexplored aspects of protein science and the recent researches in this field. Scientists and students actively engaged in this field will find this book full of crucial and unexplored concepts.