This book serves as a foundational guide to the interface between chemistry and biology, emphasizing the chemical principles underlying biological processes. It covers the structure and function of biomolecules, enzyme mechanisms, and metabolic pathways. Additionally, it explores techniques such as spectroscopy, chromatography, and mass spectrometry used in chemical biology research. The book integrates examples from current research to demonstrate the application of chemical biology in drug discovery and biotechnology. Designed for advanced undergraduates and beginning graduate students, it aims to bridge the gap between chemistry and biology. Supplementary resources include problem sets, lab protocols, and research case studies.