Columnist Desiree Cooper writes about the Walter P. Reuther Library's opening Friday of \"In the Fields (En los Campos),\" an exhibit of 30 color photos of teens from Michigan and Indiana who spend nonschool hours harvesting everything from onions to lettuce. Prizewinning documentary filmmakers Pam LeBlanc and Freddi Stevens-Jacobi set out in 2001 to honor the labor of the young migrant workers. According to the U.S. Department of Education, the United States had about 850,000 school-age migrant children in 2001. The State of Michigan offered educational services to about 13,000 children of migrant workers in 2000. About one-fifth of those kids were in grades 7-12. Exhibit hours are 9 a.m. to 6:45 p.m. Monday and Tuesday, 9 a.m. to 4:45 p.m. Wednesday through Friday. Admission is free. Contact information is provided.