"Gangsta Granny" is a children's book written by David Walliams. The story follows a young boy named Ben who discovers that his seemingly boring grandmother is actually a former jewel thief. Together, they embark on a series of adventurous escapades, blending humor and excitement. The book explores themes of family, friendship, and the importance of looking beyond appearances. It captures the imagination of young readers with its quirky characters and engaging plot, making it a popular choice for children and parents alike.