From the description on Amazon:
"This latest edition of the Field Guide to the Moths of Great Britain and Ireland has been fully revised, updated and restructured, bringing it in line with the latest thinking in taxonomy...New descriptions and illustrations have been included for species that have been newly recorded in Britain and Ireland since the last edition of the guide was published. The text descriptions of all other species - covering field characters and similar species, flight season, life cycle, larval foodplants, and habitat - have been revised and updated where necessary, and particular attention has been paid to updating the distribution information, which is now supported by maps. The revised general introduction explains how the methods of identifying and recording moths have evolved over recent years with the advent of new technologies and as a result of data analysis."
I didn't bother getting the 2nd edition and my original book is now extremely tatty so I've pre-ordered this one (release date is 9th Feb)