About Tim Zeltner Books by Tim Zeltner John Deere, That's Who! by (author) Tracy Nelson Maurer illustrated by Tim Zeltner Ages 4 to 8 Grades p to 3 Little Boo by (author) Stephen Wunderli illustrated by Tim Zeltner Ages 4 to 7 Grades p to 2 Power Down, Little Robot by (author) Anna Staniszewski illustrated by Tim Zeltner Ages 3 to 6 Grades p to 1