When he has a dream about a future Earth devastated by pollution, Walter begins to understand the importance of taking care of the environment.
- ISBN10 0395533082
- ISBN13 9780395533086
- Publish Date 1 October 1990
- Publish Status Out of Print
- Out of Print 15 December 2009
- Publish Country US
- Imprint Houghton Mifflin
- Format Paperback
- Language English