Pocket Guide to Matching the Hatch - Peter Lapsley and Cyril Bennett
Just received this little book and its very good. It details all the common flies on our rivers with examples of patterns, size, hatch charts and even rise forms. There is a good idea were the actual sizes of the various flies is shown together with an outline of the fly. The only criticism is that the patterns do not have any recipes so you have to hunt for tying details, otherwise definitely recommendable.