Despite the title, Meredith is not alone. She has a friend, Sadie, who visits often, sometimes with her kids. She has another friend, Tom, who started out seeing her as a client but who has become a pal.

She has an online job as a writer and a tight group of friends on the internet. And of course she has her dear cat, Fred.

But what Meredith does not have is a life outside the home — literally. She is 39, badly traumatized, and has not stepped foot outside of her house in more than three years. "Meredith, Alone," is the story — surprisingly upbeat and nearly weightless, in a good way — of her reawakening.

"I don't want to spend my free time reading research papers on social anxiety disorder or books about agoraphobia," she says testily, in response to brochures that the well-meaning Sadie sends her. "For the record, I don't have either of those things." And perhaps she doesn't. Still, as the book opens, she has not stepped foot outside in 1,214 days.

In flashbacks to childhood and young adulthood, the book reveals the root of her PTSD — a horrific upbringing, an abusive mother, sexual violence. Her sister Fee deals with it by fleeing into an abusive marriage, but Meredith deals with it by fleeing from the world.

Author Claire Alexander is a journalist who has written about mental illness, and that background has served her well; Meredith's two steps forward, one step back (sometimes three steps back) progress feels authentic. Her determination to get better and get outside is courageous, and the reader is with her every step — forward or back — of the way.

Laurie Hertzel is the senior editor for books at the Star Tribune. @StribBooks.

Meredith, Alone

By: Claire Alexander.

Publisher: Grand Central, 368 pages, $28.