A castaway is a person who is cast adrift or ashore. While the situation usually happens after a shipwreck, some people voluntarily stay behind on a desert island, either to evade captors or the world in general. A person may also be left ashore as punishment (marooned).
The provisions and resources available to castaways may allow them to live on the island until other people arrive to take them off the island. However, such rescue missions may never happen if the person is not known to still be alive, if the fact that they are missing is unknown, or if the island is not mapped. These scenarios have given rise to the plots of numerous stories in the form of novels and film.