The Blue Lagoon oleh H. de Vere Stacpoole

Classic novel, first published in 1908, source of the movie of the same title. According to Wikipedia, "Henry De Vere Stacpoole (9 April 1863 – 12 April 1951) was an Irish century author, born in Kingstown (now Dún Laoghaire). His best known work is the 1908 romance novel The Blue Lagoon, which has thrice been adapted into a feature film. He also wrote under the pseudonym Tyler De Saix. A ship's doctor for more than forty years, Stacpoole was also an expert on the South Pacific islands. His books frequently contained detailed descriptions of the natural life and civilizations with which he had become familiar on those islands. He moved to the Isle of Wight in the 1920s and lived there until his death. He was buried at Bonchurch in 1951."