Enid Blyton <br/><br/>
Puzzle For The Secret Seven 

<br/><br/> The gang witness the horror of a house going up in flames! Then there's the theft of a very valuable violin. Are the two incidents connected? The Seven mean to use all their detective know-how to find out! 
<br/><br/><label>ISBN: </label>9780340917633 
<br/><br/><label>Dewey Class. No.: </label>English BLY