The Hardy Boys return.

Just out from Dover Publications: books 4 and 5 in the Hardy Boys series—The Missing Chums (orig publ 1928; Frank and Joe pursue  robbers and kidnappers) and Hunting for Hidden Gold (orig publ. 1928; Frank and Joe go in aid of their injured father and locate an abandoned mine). They join The Tower Treasure (book 1, 1927), The House on the Cliff (book 2, 1927), and The Secret of the Old Mill (book 3, 1927). Canadian journalist Leslie McFarlane wrote these books as well as a memoir, Ghost of the Hardy Boys.