At the tiny public library in Winterport, Maine, 43-year-old Robert Hartmann bends over The Little Engine That Could and slowly sounds out the first line.
"Ch-chug, right?" he asks his volunteer tutor, Sandy DeLuck. "Yup," she encourages him. He presses on: "Puh-puff ... puff ... puff. Ding ... ding-dong?"
Hartmann is burly, with five facial piercings, his arms inked with tattoos. This is his second session with DeLuck. He reads at about a first-grade level.
He is one of the 35 million U.S. adults whose reading skills are below a fourth-grade level.
Thirty-five million — or 1 in 6 U.S. adults.
Nationwide, adult illiteracy has proved an intractable problem, linked to stubborn societal issues such as poverty and failing schools.
In fact, US adult literacy rates are no better than they were 25 years ago.