Book excerpt: Published on behalf of the Biological Stain Commission For 75 years Conn's Biological Stains has been a standard reference for all those who used dyes and colorants in the biological and medical sciences. This long awaited tenth edition appears 25 years after R.D. Lillie's ninth and has been completely rewritten to reflect the increase in range of uses. Although the staining of microscopical preparations continues to expand the uses of dyes and fluorochromes now extend far beyond this traditional application. This book provides the first critical overview of the whole range of low molecular weight fluorescent probes, outside the catalogue literature. The first ten chapters are essays, by leading experts, on the important aspects of colorants and their uses. Most of the remainder of the book consists of descriptions by Dr Horobin of the properties and recent applications of hundreds of individual compounds, in about twenty chemical classes. The last chapter reviews the procedures employed at the Biological Stain Commission's laboratory to assay and test dyes and certify them as suitable for their intended applications.