"Caddis larvae that build and carry cases of mineral and plant materials are some of the most conspicuous members of the British freshwater fauna. Nevertheless the ecology of these case-bearers is poorly known because, until recently, it has been difficult or impossible to identify many of the species and the lack of detailed keys for identification has hampered or prevented research on their biology and ecology. This situation will now be redressed, I hope, by the publication of the first FBA key to the case-bearing caddis larvae of Britain and Ireland. ...The key will, I am sure, prove to be a worthy companion for the FBA key to caseless caddis larvae (No. 43 by J.M. Edington & A.G. Hildrew, 1981). Unlike it and other recent FBA Scientific Publications the new key does not have a separate section of ecological notes, although brief mention is made of distributions and habitats at appropriate places in the text. With this minor caveat emptor in mind I am certain that all will welcome the long-awaited publication of this key." (J.G. Jones, Director).