The Motor Boys on A Ranch is the 18th in the series. Ned Slade’s father owns a cattle ranch out west that has been plagued with cattle rustlers. You’d think the ranch’s cowboys could just track the cattle and get them back, but the rustlers and the herd seem to just disappear into thin air! It’s a mystery all right, and solving a mystery is exactly what the boys are looking to do over their summer vacation from college. Ned's dad hires a private detective just in case the boys fail. Fail? The boys? Nonsense!

Clarence Young was a Stratemeyer Syndicate pen name. Howard Garis almost certainly wrote the series, although Stratemeyer usually provided his authors with an outline of the books. Garis and his wife, Lillian, wrote many children’s books under their own name. They are best known for a series of books that featured the character of Uncle Wiggily Longears, an engaging elderly rabbit. Many of Garis’ books were illustrated by Lansing Campbell. Garis and his wife, Lilian Garis, were possibly the most prolific children's authors of the early 20th century. Garis wrote many books for the Stratemeyers Syndicate as well, over a period of some 30 years.