Ada Hopper 
Revenge of Dr. von Naysayer 

In the tenth DATA Set adventure, the kids must choose sides in the battle between Dr. Bunsen and Dr. Von Naysayer!Dr. Bunsen goes up against his ultimate nemesis, Dr. Von Naysayer to settle their long-standing feud, once and for all. May the best mad scientist win! With easy-to-read language and illustrations on almost every page, the DATA Set chapter books are perfect for emerging readers.