Nanoindentation is ideal for the characterization of inhomogeneous biological materials. However, the use of nanoindentation techniques in biological systems is associated with some distinctively different techniques and challenges. The book presents the basic science of nanoindentation, including the background of contact mechanics underlying indentation technique and the instrumentation used to gather mechanical data. It provides perspectives that are optimized for biological applications, including discussions on hydrated materials and adaptations for low-stiffness materials. The book also covers the applications of nanoindentation technique in biological materials. Highlighting current challenges, it concludes with an insightful forecast of the future.