Gus and his grandfather celebrate Halloween together in this eighth entry in the series by Mills and Stock (Gus and Grandpa at Basketball, 2001, etc.). Gus has a problem to solve: his parents don’t approve of store-bought Halloween costumes, and they think their son can come up with his own. He appeals to Grandpa, who luckily has a trunk full of family clothing in his attic. Grandpa finds a Canadian Mountie uniform worn by Gus’s father as a Halloween costume when he was a boy. Gus proudly tells his friends, “My grandma made it for Daddy when he was a little boy.” In a satisfying conclusion, Gus’s father takes a picture of his son in the uniform, with Grandpa standing nearby. Mills quietly shows Gus solving his own problem, both in figuring out a suitable costume and in handling how he presents his heirloom costume to his friends. Stock’s understated watercolor illustrations in muted fall tones complement the story well, and she captures Grandpa’s warm affection for his grandson. This mid-level easy reader will also work well as a Halloween read-aloud both for younger children and for the early elementary grades. (Easy reader. 6-8)