Blyton, Enid <br/><br/>
Five go to billycock hill 

 - London  Hodder Children's Books  1997 
 - 185 
 - Famous five .
<br/><br/> "The Famous Five have made a new friend -- a pilot! But he has disappeared with top secret equipment. The Five can't believe it -- is Jeff a traitor?"--Page 4 of cover 
<br/><br/><label>ISBN: </label>9780340681213 
<br/><br/><label>Dewey Class. No.: </label>823  / BLY-F