Clark's first book, "The Donkeys" (1961), was a revisionist history of the British Expeditionary Force's (BEF) campaigns at the beginning of the First World War. The book covers Western Front operations during 1915, including the offensives at Neuve Chapelle, Aubers Ridge and Loos, and ending with the enforced resignation of Sir John French as Commander-in-Chief of the BEF, and his replacement by Douglas Haig. Clark describes the battle scenes, and criticises the actions of several of the generals involved in the heavy loss of life that occurred. Much of the book is based on the political manoeuvres behind the scenes as commanders jostled for influence, and Sir John French's difficulties dealing with his French allies and with Herbert Kitchener. Haig's own diaries are used to demonstrate how Haig positioned himself to take over command. The publication sold well, and is still in print 50 years after its first print run, being regarded as an important work on the British experience of the World War.