Laser-enabled measurements are valuable tools for the investigation of surfaces and interfaces or for the in situ investigation of interfacial processes including electrode processes. The understanding of the thermodynamics of solid/liquid surfaces is important for surface science and electrochemistry. In the first part of this book, the authors describe a range of techniques for investigating interfacial tension and surface stress, which is important for coatings, thin films, and fuel cells. The techniques covered comprise bending beam (bending plate, bending cantilever, wafer curvature) methods with different detection techniques. Special attention is given to methods using optical detection by laser beam deflection or interferometry. The second part is