Editor's note: This is a Patriot Ledger special project.
More sidebars/graphics available on Patriot Ledger Web site.
More photos available on the CNC ftp in "Special Education."
Massachusetts spent $1.8 billion on 163,396 special needs students last year. It costs twice as much to educate a special ed student in the state, which is seventh-highest in the nation for special ed enrollment.