Grosset and Dunlap. Copyright 1936. Print run Carpentieri-coded 1947A-17. Cover art by J. C. Gretta. Author was Leslie McFarlane, using the Stratemeyer "Dixon" house pseudonym. The term "Sign Post" was changed to "Signpost" in later versions. #15 in the series. Brown book in near fine condition with orange Gretta endpapers, plain frontispiece. Original 25 chapters. No internal book titles list. Tanned but not brittle war-time paper (in effect through 1948). No writing. Sturdy binding and hinges without tracking. No visible corner damage. Yellow spine and "The Hardy Boys" supra-title in block letters. Very nice dust jacket with some chipping at spine and minor wear at top front corner side. There's a wrinkled area at the bottom of the spine, which the removable mylar cover now protects. "6565" and "110-150" on front flap. Front flap last title is ten volumes later, The Secret Panel. Rear flap lists Lone Ranger titles to Rides Again. Rear of jacket lists 23 aviation titles. The first picture above was taken with the mylar cover the book is in, and the others show the book without the mylar. (RHB-15 )