![](/images/cover/.tmb/thumb_0448436981-L_100_200.jpg)
The Pentagon Spy is the 61st title of the Hardy Boys series., written by Franklin W. Dixon. Grosset & Dunlap published this book in 2005.
![](/images/cover/.tmb/thumb_0448089262-L_100_200.jpg)
The Phantom Freighter is Volume 26 in the original The Hardy Boys Mystery Stories published by Grosset & Dunlap. This book was written for the Stratemeyer Syndicate by Amy McFarlane, the wife of long time Hardy Boys author Leslie McFarlane, in 1947. Between 1959 and 1973 the first 38 volumes of this series were …
![](/images/cover/.tmb/thumb_0448089467-L_100_200.jpg)
The Secret Agent on Flight 101 is Volume 46 in the original The Hardy Boys Mystery Stories published by Grosset & Dunlap. This book was written for the Stratemeyer Syndicate by Tom Mulvey in 1967. Mulvey was also responsible for editing other Stratemeyer Syndicate stories with aviation content.
![](/images/cover/.tmb/thumb_0448089254-L_100_200.jpg)
The Secret Panel is Volume 25 in the original The Hardy Boys Mystery Stories published by Grosset & Dunlap. This book was written for the Stratemeyer Syndicate by Harriet S. Adams in 1946. Between 1959 and 1973 the first 38 volumes of this series were systematically revised as part of a project directed by Harriet …
![](/images/cover/.tmb/thumb_0448189178-L_100_200.jpg)
The Secret Warning is Volume 17 in the original The Hardy Boys Mystery Stories published by Grosset & Dunlap. This book was written for the Stratemeyer Syndicate in collaboration by John Button and Leslie McFarlane in 1938. Between 1959 and 1973 the first 38 volumes of this series were systematically revised as …