Jacob Wrestling is a fictional book in the novel I Capture the Castle by Dodie Smith. It was written by James Mortmain, the father of the main character. It is described as a strange book, part novel, part poetry, part philosophy. Much of the plot of I Capture the Castle is about how Mortmain as developed crippling writer's block and is unable to write another book. He and his family is living in semi-genteel poverty in an absurdly grand old castle. His children scheme to get him to write again.