Cary now undertook his great works examining historical and social change in England during his own lifetime. The First Trilogy (Herself Surprised -1941, To Be a Pilgrim - 1942, and "The Horse's Mouth" -1944) finally provided Cary with a reasonable income, and "The Horse's Mouth" remains his most popular novel. Cary's pamphlet "The Case for African Freedom" (1941), published by Orwell's Searchlight Books series, had attracted some interest, and the film director Thorold Dickinson asked for Cary's help in developing a wartime movie set partly in Africa. In 1943, while writing "The Horse's Mouth", Cary traveled to Africa with a film crew to work on "Men of Two Worlds".