The inspiration for this volume lies in Edisbury's Practical Hints for Absorption Spectrometry which was published 17 years ago. Dr Edisbury was a founding member of the Photoelectric Spectrometry Group, served as its first Secretary and edited the Bulletin for many years. His wisdom, humour and pragmatism was evident in early meetings of the Group and in the first issues of the Bulletin, and these qualities were distilled in the writing of Practical Hints. In 1977, the Committee of the Group, which by then had been re-named The UV Spectrometry Group, decided to make use of the expertise available amongst the members of the Group in writing some monographs on the practice of UV and visible spectrometry. Working parties were set up which formulated and produced the first two volumes of the series on Standards in Absorption Spectrometry and Standards in Fluorescence Spectrometry. The success of these volumes lead the present Committee of the Group to set up a new Working Party in 1981 to plan a modern version of Edisbury's book. The idea really caught fire' at the first meeting of the Working Party, when ideas sufficient to fill ten vol umes were put forward. We would not pretend to emulate Edisbury's unique style, but hoped to produce a readable book for the newcomer to UV -visible absorption spectrometry, and perhaps to improve the technique of more experienced users.