What was the name of the first Hardy Boys book?

Hardy Boys, brothers Frank and Joe Hardy, are fictional characters who appear in several mystery series for children and teens. The series revolves around teenagers who are amateur sleuths, solving cases that stumped their adult counterparts. The characters were created in 1926 by American writer Edward Stratemeyer, the founder of book-packaging firm "Stratemeyer Syndicaye."

The first Hardy boy book was 1927's "The Tower Treasure". The books themselves were written by several ghostwriters, most notably Leslie McFarlane, under the collective pseudonym Franklin W. Dixon. Stratemeyer pitched the series to publishers "Grosset & Dunlap."

The first three titles were published in 1927, and were an immediate success: by mid-1929, more than 115,000 books had been sold. So successful was the series that Stratemeyer created Nancy Drew as a female counterpart to the Hardys.

The Hardy Boys have evolved since their debut in 1927. From 1959 to 1973, the first 38 books were extensively revised, largely to remove depictions of racial stereotypes; they were also targeted towards younger readers by being rewritten in a simpler, action-oriented style to compete with television.