The chapter "Characterization and Analysis of Porosity and Pore Structures" by Lawrence M. Anovitz and David R. Cole provides a comprehensive overview of the importance and methods for quantifying porosity in geological materials. Porosity plays a crucial role in controlling fluid storage, transport, and rock properties, making it essential for understanding geological systems. The authors highlight the historical significance of porosity studies, dating back to TS Hunt's work in the 19th century, and the extensive data collected by Manger (1963) on sedimentary rocks. The chapter outlines various techniques for measuring porosity, including saturation, buoyancy, gas expansion, gas adsorption, and mercury intrusion porosimetry. Each method is described in detail, with specific equations and examples provided to illustrate their applications. For instance, the saturation method involves weighing a dry rock sample, saturating it with a wetting fluid, and then measuring the weight of the saturated sample to determine porosity. The buoyancy method uses the same principles but involves suspending the saturated sample in a fluid to account for the weight of the fluid displaced. Gas expansion methods, such as helium porosimetry, are highlighted for their accuracy in measuring effective porosity in low-permeable rocks. Gas adsorption techniques, particularly N₂ adsorption, are discussed for their ability to characterize pore surface area and volume, especially in fine-grained materials like mudrocks and coals. Mercury intrusion capillary pressure (MICP) is described as the standard method for characterizing pore features, particularly pore throat size distributions, over a wide range of scales from microns to nanometers. The Washburn Equation is explained, which relates the pressure required to force mercury into pores to their size and shape. Imaging methods, including optical petrology, scanning electron microscopy (SEM), focused ion beam SEM (FIB SEM), and X-ray tomography, are also covered. These methods provide detailed visual information about the pore system and associated mineralogy, complementing traditional petrophysical techniques. The chapter emphasizes the importance of combining multiple techniques to gain a comprehensive understanding of pore structures in complex geological materials. Overall, the chapter aims to provide a practical guide for researchers and practitioners in the field, offering a detailed review of the various techniques available for analyzing porosity and pore structures in rocks and other porous materials.The chapter "Characterization and Analysis of Porosity and Pore Structures" by Lawrence M. Anovitz and David R. Cole provides a comprehensive overview of the importance and methods for quantifying porosity in geological materials. Porosity plays a crucial role in controlling fluid storage, transport, and rock properties, making it essential for understanding geological systems. The authors highlight the historical significance of porosity studies, dating back to TS Hunt's work in the 19th century, and the extensive data collected by Manger (1963) on sedimentary rocks. The chapter outlines various techniques for measuring porosity, including saturation, buoyancy, gas expansion, gas adsorption, and mercury intrusion porosimetry. Each method is described in detail, with specific equations and examples provided to illustrate their applications. For instance, the saturation method involves weighing a dry rock sample, saturating it with a wetting fluid, and then measuring the weight of the saturated sample to determine porosity. The buoyancy method uses the same principles but involves suspending the saturated sample in a fluid to account for the weight of the fluid displaced. Gas expansion methods, such as helium porosimetry, are highlighted for their accuracy in measuring effective porosity in low-permeable rocks. Gas adsorption techniques, particularly N₂ adsorption, are discussed for their ability to characterize pore surface area and volume, especially in fine-grained materials like mudrocks and coals. Mercury intrusion capillary pressure (MICP) is described as the standard method for characterizing pore features, particularly pore throat size distributions, over a wide range of scales from microns to nanometers. The Washburn Equation is explained, which relates the pressure required to force mercury into pores to their size and shape. Imaging methods, including optical petrology, scanning electron microscopy (SEM), focused ion beam SEM (FIB SEM), and X-ray tomography, are also covered. These methods provide detailed visual information about the pore system and associated mineralogy, complementing traditional petrophysical techniques. The chapter emphasizes the importance of combining multiple techniques to gain a comprehensive understanding of pore structures in complex geological materials. Overall, the chapter aims to provide a practical guide for researchers and practitioners in the field, offering a detailed review of the various techniques available for analyzing porosity and pore structures in rocks and other porous materials.