Books specifically on Swaziland are thin on the ground, unless you'd like to burrow into such erudite tomes as The economic impact of the adoption of hybrid maize in Swaziland. You could, however, try the following:Michael Brett and Alan Mountain's Touring Atlas of Southern Africa offers a short but colourful section on Swaziland.The Complete Guide to Walks & Trails in Southern Africa by Jaynee Levy covers all the trails and contains an extraordinary amount of information, although it is far too big and heavy to carry.Mammals of Southern Africa by Chris and Tilde Stuart includes a stack of information and excellent photographs.Kenneth Newman's Newman's Birds of Southern Africa is a comprehensive field guide with full-colour illustrations.