This volume contains eight chapters covering a wide range of topics: ultrasonic vibration potentials, impedance measurements, photo­ electrochemical kinetics, chlorine production, electrochemical behavior of titanium, structural properties of membranes, bioelec­ troche mistry, and small-particle effects for electrocatalysis. Chapter 1, contributed by Zana and Yeager, discusses the little used but potentially important area of ultrasonic vibration potentials. The authors review the historical literature and the associated theoretical equations. They continue by discussing various aspects of the experimental technique and close with a review of the existing studies. They conclude by noting that vibra­ tion potentials may be useful for determining the effects of various agents on colloidal suspensions found in such important industries as paper production. Chapter 2 is a review of impedance techniques, written by Macdonald and McKubre. The authors include not only derivations of various impedance functions for electrochemical systems but also particularly useful discussions of instrumental methods. The authors close with an interesting claim: "the distribution of current and potential within a porous battery or fuel-cell electrode and within 'flow-through' electrodes is best analyzed in terms of the frequency dispersion of the impedance." Chapter 3, by Khan and Bockris, is a timely review of photo­ electrochemical kinetics and related devices. Their work begins by reviewing critically important papers on photoelectrochemical kinetics. They continue by presenting detailed discussions concern­ ing the conceptual ideas of the semiconductor-solution interface.