The Hardy's invention, Roger the Lobber, an automatic tennis ball retrieval and return unit, has been stolen from the Teen Inventor's Club competition and then reappears without warning, transformed into a device of danger.
- ISBN10 0606058583
- ISBN13 9780606058582
- Publish Date 1 January 1993
- Publish Status Out of Print
- Out of Print 25 March 2015
- Publish Country US
- Imprint Demco Media Inc
- Edition Turtleback School & Library ed.
- Format Hardcover
- Pages 152
- Language English