Are there any realy good books in print on sloping gardens

Try looking up terraced gardens? Amason have loads of books on terraced gardens. So do Libraries and second hand book shops as the principles of terracing are the same. Then you can chose more modern materials and planting if prefered. When I had a sloping garden the designer put in a large patio and made 2 terraces, very large rocks in the first terrace with rockery plants and big shrub plants in the second. Between the terraces were lawns and trees with another patio area at the top. You need good non slip paths. Its great fun to create and lighting it is great. good luck