Gilbert's most celebrated works include "King Arthur's Knights: The Tales Retold for Boys and Girls" (1911) and "Robin Hood and the Men of the Greenwood" (1912), both of which brought medieval legends to life for generations of children. He also wrote "Stories from the Operas" (1913), "Pirates and Their Ways" (1914), and "The Book of Courage" (1920), a collection of stirring historical tales of bravery and adventure. In addition, he adapted Shakespeare for younger audiences, producing works such as "The Tale of Cymbeline" (1918).
Gilbert spent much of his later life in Norfolk, where the rural landscape and folk traditions enriched his writing. Although less widely known today, his retellings helped shape the way classic stories were presented to young readers, and his books remain valued examples of early twentieth-century children's literature.