In the Introduction to Volume One of this series, the stated objective was to provide as broad as possible cover of the physical, inorganic, organometallic, and organic aspects of photochemistry in a unified way that would ncourage interactions between workers in particular areas. Over the years, we introduced further topics, particularly polymer photochemistry and the chemical aspects of solar energy conversion. On the other hand, we have reluctantly been obliged to discontinue the coverage of gas phase and inorganic photochemistry. As a new feature, we have decided to introduce occasional reviews of specialised areas of photochemistry, starting with a review of photochemistry at surfaces by Dr.S.R.Meech. In selecting future topics for review, we shall aim for timeliness, as in the present case. We take this opportunity to invite suggestions for future occasional reviews of this type, and would be particularly pleased to hear from colleagues willing to accept the great honour of writing them! With these developments, we hope to return closer to the objectives originally set out in Volume One.