Through the medicine cabinet /
by Dan Greenburg ; illustrated by Jack E. Davis.
- New York : Grosset & Dunlap, c1996.
- 57 p. : ill. ; 20 cm.
- The Zack files ; 2 .
- Greenburg, Dan. Zack files ; 2. .
After Zack opens his medicine cabinet one morning and sees a boy who could be his double staring back at him, he enters a parallel universe.