This substantial book is both an unusual military memoir and a fascination exploration of an almost forgotten episode in Anglo-Spanish military history. The 'British Legion' of the title has nothing to do with its 20th Century namesake, but was the name of an expeditionary force raised in 1837 to fight in the First Carlist War - a bitter dynastic dispute. Don Carlos, brother of the deceased Spanish King Ferdinand, refused to accept the succession of his infant neice Isabella, and raised the standard of revolt in the ultra-conservative Navarre and Basque provinces of northern Spain. Britain and France, fearing instability, sent forces to shore up the relatively Liberal Madrid regime against the Carlists. The campaign that followed was messy, inconclusive, and, according to Somerville's account, characterised by incompetence, cowardice and even mutiny - mainly on his own side. The narrative switches between accounts of bloody battles at Irun and St Sebastian, comparisons with the Peninsular War fought over the same terrain only a quarter of a century before, and near-farcical episodes when the author makes no attempt to disguise his disgust with his own side. An inglorious episode in British arms by any standard, it is scarcely surprising that the Carlist Wars are today terra incognita, even to military buffs. This book should go a long way towards filling a gap in our knowledge. It is accompanied by appendices listing the Legion's Nominal Roll etc.