Evans, M. & Edmondson, R. (2007) A Photographic Guide to the Grasshoppers & Crickets of Britain & Ireland. WGUK.
Pinchen, B.J. (2006) Pocket Guide to the Grasshoppers, Crickets and Allied Insects of Britain and Ireland, Forficula Books
The Natural History Museum & Ovenden, D. (2004) Guide to British grasshoppers and allied insects, Field Studies Council fold-out chart
Haes, E.C.M. & Harding, P.T. (1997) Atlas of grasshoppers, crickets and allied insects in Britain and Ireland. CEH.
Brown, V.K. (1990) Grasshoppers – Naturalist’s Handbooks. Slough: Richmond Publishing.
Marshall, J.A. & Haes, E.C.M. (1988) Grasshoppers and allied insects of Great Britain and Ireland. Colchester: Harley.
There is an inspiring list of books on Orthoptera at http://www.pembooks.demon.co.uk/new07.html