This book focuses on the fundamental principles and applications of several modern biochemical and biophysical techniques employed in molecular and cellular biology. It describes cutting-edge techniques for studying single molecules/biomolecules, subcellular structures, and cells. The book chapters provide an in-depth understanding of methods currently employed to visualize and probe molecular and cellular processes. The techniques discussed in this book include Mass spectrometry, Microscopy techniques, Forster resonance energy transfer (FRET), Z-scan, Fluorescence correlation and cross-correlation spectroscopy, Dynamic light scattering (DLS), X-ray crystallography, Total internal reflection fluorescence (TIRF) microscopy, Cryo-EM, NMR spectroscopy, Optical tweezers, Magnetic tweezers, Raman spectroscopy, Atomic force microscopy (AFM), Optogenetics, bioinformatics, etc. The book chapters also include the biomedical, industrial, and R&D applications of these methods. Also included are sections on data analysis and its interpretation. Overall, this book offers a comprehensive and detailed understanding of several modern techniques in molecular and cellular biology.