The text is appropriate for graduate student s reference and provides the essential groundwork for an advanced understanding of the various mechanisms that may result in altered activity of a specific cell protein in relation to gene expression. This book mainly focusing on two aspect, gene regulation and cell signaling regulation process. Part I focuses on approaches for studying control of mRNA expression and determining target genes for a given transcription copy and the methods for determining how proteins can regulate each other by mediating synthesis, degradation, protein-protein interactions, and posttranslational modification etc. Part II explores the different types of cell signaling process, signaling molecules and their mechanism.