The Practical Entomologist, Rick Imes, This is a very good book, ideal for those thinking of entomology as a hobby and probably the only easily readable book on the subject.
Top Wildlife Spots, This is a superb guidebook covering 200 of the UK’s nature reserves owned and managed by the Wildlife Trusts.
RSPB Complete Birds of Britain and Europe, Rob Hume. A high quality reference work that includes details on the 800 species of birds most often found in Britain and Europe, with full page profiles of the most important 320 species, each supported with high quality photographs. At nearly 500 pages it might be a little large to use in the field, but is an invaluable reference work.