According to this salute, the author's grandfather, T.H., was an eccentric variant of Clarence Day's behemoth--a tyrant of home and office and absolute monarch of his Marblehead, Mass. estate. But unlike Day's father, T.H., deaf as a haddock, could also be a terror to the forces of local law and order, and possessed remarkable physical endurance on land and sea. The author begins by noting the vibrations among the 1938 Sunday morning household as T.H. fires off his weekly volley from a roof-based cannon 'cross the bay. Among the outraged-to-delighted were a passel of grandchildren, a gentle wife, spinster Aunt Rhoda, a free-loading widow, guests and other kin, and Uncle Cy, T.H.'s pride and despair. It was Cy who teamed with his father through two storms at sea and the famous motor car race into Boston. But Cy also masterminded the theft and sinking of both the cannon and Pierce Arrow for the health and safety of family and neighborhood. The many views of T.H.--in his Boston office ""that would have rocked Charles Dickens back on his heels,"" on the chauffeured race against the morning train, during the rigors of Sunday tennis--are broadly funny, and the story of tragically doomed Cy is cut along the same affectionate, lightly sentimental bias. Ingratiating entertainment.