From the foreword:
"The British Isles are possibly unique in having a large resident army of amateur entomologists who freely exchange information without seeking any reward. The Biological Records Centre facilitates this exchange of information on a much larger scale than was possible previously, but the source of records remains the same. This Provisional Atlas of Larger Brachycera is one of many such publications derived almost entirely from the efforts of amateur naturalists, the group having received little study by academics and even less by professional entomologists in Britain.
One reason for this neglect is that most of these flies cannot be regarded as having major economic importance. The horse flies (Tabanidae) are a possible exception, being potentially important as disease vectors, and the female feeding habits can cause problems for livestock. Most of the larvae of Larger Brachycera are predatory and they must have some influence on pest populations in certain habitats, but their importance has yet to be evaluated.
The group includes some of the most spectacular flies found in Europe. Many of them are sun-loving insects, fond of sitting in open situations where they attract the attention of the casual observer. The British Isles fauna is relatively poor in species, many of which are very local in distribution, and few dipterists have specialised solely in them. On the other hand, almost all dipterists collect or record them, albeit on a casual basis, so that the Larger Brachycera Recording Scheme has been able to gather sufficient records to warrant this provisional atlas."