Motherhood may be the world's most complicated job, but when a child has autism and a host of other developmental disorders, the challenges are even tougher. With "Next Stop" (Putnam/Aimy Einhorn Books, 288 pages, $25.95), Glen Finland has written a memoir of wonderful insight and emotional honesty about her fearsome love for her autistic son, David, who seeks to move from adolescence into adulthood in a world that doesn't always understand the differently abled. It may sound like a dark story, and sometimes it is, but Finland lightens it with self-effacing humor and impressive skill in describing small episodes that illuminate larger truths.

For David, who can't manage to comprehend the social cues and emotions of others, independence will never be simple. Finland fears that David's inability to "read" others will make him an easy mark for bad-intended strangers. She struggles with letting go, with when to stop micromanaging his life as he grows into manhood.

At 21, David needs to navigate the Washington, D.C., Metro system if he's to find a job and live on his own. Finland opens the book with an account of riding the train every day with David. When he's ready to ride on his own, Finland secretly follows him: I "slip into the crowd after him. From there I shadow him without his knowing it, darting behind a commuter's newspaper like a bad spy movie."

Finland repeatedly finds ways to be positive in bad situations. Once, after David has taken public transportation and gotten lost at night in one of Washington's tougher neighborhoods, she rushes to pick him up. When he's safe in the car, she declares the incident "a double victory": "first, nothing bad happened. Second ... David is learning to keep safe alone in the world." In another episode, David and his mother are riding on a crowded subway train when a large man accidentally steps on the author's toes. As Finland's face contorts in pain, David has a small epiphany: "He didn't mean it, Mom," A now-pleased Finland recognizes that "empathy for a stranger is something brand-new for David. Good stuff."

Of course, Finland submerges her needs in order to help supremely needy David. She also recognizes that she's at times neglected her other two sons, and her husband. She admits to "a creeping sense of guilt." But David makes progress, getting his driver's license, finding a job, attracting a few friends. Readers can almost feel David's desire to be independent, and Finland's desire to have him launch successfully into the adult world. She ends this love-fueled and enlightening memoir with an image of her son alone on the train: "As the train pulls away, I catch a last glimpse of a young man standing in the middle of the aisle, focused and unescorted, looking into the darkness for his place in the world." One can't help but wish them both well.

Chuck Leddy is a member of the National Book Critics Circle. He lives in Boston.