Mister Lester is Grover's very first teacher in the Sesame Street book Grover Goes to School. Grover is very nervous being in his class, and has many good gestures go wrong. When Mister Lester dismisses the children for milk and cookies, he instructs them they must clean up their messes first, but eager Grover sends them all on their way while he tries impress them by cleaning up himself, resulting in the cookies being all gone before he gets there.