After Hargreaves died in 1988 , his son , Adam Hargreaves , began writing and illustrating new stories about the Mr. Men and Little Miss characters . He created ten new characters ; four of them were inspired by work Roger Hargreaves had produced before his death . After Hargreaves 's death in 1988 , his son Adam Hargreaves began writing and illustrating new stories , including four characters that R. Hargreaves had developed before his death .