The tremendous amount of research that has been carried out in the two closely related fields of semiconductor photoelectrochemistry and photocatalysis during the past three decades continues to provide fundamental insights and practical applications. The present review paper will attempt to describe some of the progress and resulting achievements in these two areas and to briefly discuss the future prospects. In order to provide a focal point, we will highlight work carried out in Japan over the last 5 years. However, we will try as much as possible to put this work into a global and historical context by tracing some of the key developments that have occurred outside this relatively narrow scope. We should note at the outset that we have made no attempt to cover the underlying theory or physics of photoelectrochemistry. Several excellent reviews have appeared during this same time period that cover fundamental and general aspects of photoelectrochemistry and photocatalysis.