This second edition of Peter Grant's guide has been extensively revisedand has been reset throughout. Importantly, a further eight species ofgulls occurring on the west coasts of Canada and the USA have beenadded. Thebook now covers 31 species and has been increased in length from 280 to352 pages. More than 280 new photographs have been added orsubstituted, bringing the total to 544, including 79 photographs forthe eight North American additional species. The greatincrease in interest in gull identification since the publication ofthe first edition (and the author's series on that topic in BritishBirds) has helped bring much new information to light. As a result somerevision was made to almost every text page and most of theidentification drawings were improved in some way; in addition, changeswere made to many of the distribution maps. These revisions andimprovements were often quite minor, but others were substantial andimportant (see the author's Introduction). Until recentlygulls were widely regarded as a difficult group and identification andageing was often inaccurate or uncertain. This was largely due to thecomplexities of immature plumages, which of necessity were generallyunrepresented in standard field guides. Birdwatchers need no longer bedeterred or confounded by that deficiency. The book offers them theopportunity to advance their skill in field identification by acceptingthe challenge rather than shrinking from the difficulties.