The formulation of our proposals for mires and heaths, which make up this second volume of British Plant Communities, occupied much of the middle years of the National Vegetation Classification project, when the enthusiasm of the research team could so easily have flagged and the financial support of the Nature Conservancy Council been put in jeopardy but for a continuing faith in the quality and value of the results.

As coordinator of the project and editor of the work, I owe a special and very substantial debt in the preparation of the accounts of the mire communities to Michael Proctor. With Paul Wilkins, the research assistant who worked under his supervision with great industry and wit, Michael undertook the analysis of a very large body of data collected by our own team together with numerous samples from existing work, and he prepared preliminary descriptions of most of the vegetation types. Both in these earlier stages and later, when together we shaped the proposals into a coherent whole and I completed the writing of the community accounts, I was enormously informed by Michael's experience of mire ecology and his always thoughtful comments on the developing scheme.

As the classification emerged, we were both helped greatly by the prodigious efforts of Dr Hilary Birks who, on secondment to the team for a brief period, confirmed the integrity of many of the vegetation types in a parallel analysis of upland data. Among other workers, we are especially grateful to Dr Bryan Wheeler, not just for his generosity in allowing us unhindered access to his numerous data from base-rich mires, but also for the open-hearted way in which he shared his understanding of mire vegetation and gave us enthusiastic critical comments.

As throughout our work, we are also pleased to acknowledge the assistance of Messrs Eric Birse and James Robertson of the Macaulay Institute in Aberdeen who supplied us with many data from Scotland. We are grateful, too, to Dr Peter Hulme also of the Macaulay, and to Drs Eric Bignal, Mike Clarke and Roger Meade, Miss Ros Hattey, Mr John Ratcliffe and various staff of the England Field Unit, then under the leadership of Dr Tim Bines, for enabling us to draw upon NCC reports on mire vegetation.