The Secret Panel, The Hardy Boys Mystery Stories #25 in the series. Author: Franklin W. Dixon. 178 printed pages pages. Hardcover book. Publisher: Grosset & Dunlap, copyright 1969, printed in 1974 in the U.S.A.

Synopsis:  Frank and Joe Hardy become involved in a strange mystery after helping a motorist whose car has overturned. The man identifies himself as John Mead, but when the boys later find an unusual key belonging to him, they discover that Mead supposedly died five years earlier. Their curiosity leads them to the mysterious Mead mansion, a strangely constructed house with concealed locks and no visible doorknobs or keyholes. At the same time, their detective-father, Fenton Hardy, is investigating a gang responsible for a series of robberies involving televisions and stereo equipment.

As Frank and Joe pursue both mysteries, they discover that the mansion and the criminals are connected. The boys encounter a secret panel and become increasingly entangled with the gang, while clues involving a mysterious device capable of defeating locks and alarm systems reveal why the criminals are so interested in the old house. The 1969 revision, shortened from the original and condensed into 20 chapters, retains the basic storyline but removes several episodes and updates the criminals' activities to make the story feel more contemporary.

Condition: The book is in very good condition.  The covers have some light wear on the corner tips, and the blue spine cover has a small 1/4" tar on the blue cloth just above the author's name and some light wear on the bottom and top edges of the blue .  The inside pages are in excellent condition with no writing, and the binding and spine are also in very good condition (see photos).