This book covers the wide range of methods, which have become standard tools in every biology, material science, surface science, and optics laboratory: those that measure tip-sample interactions with forces and those that measure tip-sample interactions with currents. It emphasizes the fundamentals that may be applied to basic through advanced applications, including such topics as van der Waals forces between macroscopic objects, strain-stress analysis, continuum deformation theory, friction theory at the microscopic level, control theory, and an introduction to surface states and surface reconstruction.