The book provides a broad overview of an important biological system -- 'cell membrane'. The cell is the powerhouse where processes of life are controlled. Cell membranes consist of lipid bilayers that make biological boundaries. The bilayer participates in determining most of the cell-based uptakes of materials, exchanging of information between both sides and ensuring helping vital biological processes to continue. We have focused specifically on an understanding of various aspects of lipid membrane bilayers. The book is focused on a detailed description of the diverse mechanisms and phenomena associated with membranes. Lipid bilayers exist in various parts of the cell, namely, across the plasma membrane, mitochondrial membrane, and nuclear membrane. While exploring lipid bilayers we shall, therefore, need to consider structures and functions of various sections of biological cells. Besides spectroscopic observations and electrical measurements of membrane bilayers, we address here the phenomena of coexistence and independent existence of different membrane components using various theoretical and experimental methodologies popularly used in biology, physics, mathematics, chemistry, biomedical engineering, and general medical sciences. The focus has been made on explaining diverse mechanisms that play crucial roles in molecular level in the construction of lipid bilayers and maintaining the relevant biological functions. This book will be helpful for readers who want to understand biological processes by applying both simple observations and fundamental scientific analysis. It provides a deep understanding of the causes and effects of molecular processes inside lipid bilayer membranes. A group of eminent scientists from around the globe contributed chapters focusing on different aspects. Each chapter may be found to present an individual topic and elaborate on a specific problem. But the chapters altogether have covered most of the basic aspects relevant to the title of the book. The book will be a vital reference for scientific understanding of lipid bilayers.