Back in 1986, when he was 20 years old, a Massachusetts resident named Christopher Knight drove to Maine, steered his car as deep into the forest as he could go, and turned off the engine. He placed the keys on the center console and walked off into the trees. For the next 27 years, he lived in the woods. In all that time, he communicated with no one, other than two hikers he happened to encounter five or 10 years on. (He said, "Hi.")

No one knew where he was. He didn't get in touch with his parents, nor his brother (who had co-signed for the car and was stuck with the payments), nor the people at his job. He just vanished.

But he didn't vanish very far. The Maine forests are dense and Knight found an almost invisible spot behind two "elephant-sized" boulders, within walking distance of a popular lake. It was there, behind those rocks, that he lived for nearly 30 years.

What a fascinating story! It might be more interesting, though, if Knight had become a true hermit, withdrawing from society and living fully on his own. Catching squirrels, maybe, or growing his own lettuce. And it might be more interesting still were he able to articulate why he had done this.

But Knight became a parasite, living off of others — breaking into cabins and stealing whatever he needed or wanted: food, yes, but also mattresses and books and blue jeans and tarps and radios and books and eyeglasses and batteries (lots of batteries).

Legends grew up around him, as well as fears; cabin owners felt like they were being watched. (They were — except for one mistake, Knight broke in only when they weren't home.)

When Knight was finally caught (this is the dramatic opening of Michael Finkel's "The Stranger in the Woods") it was while he was breaking into a children's summer camp that he had burglarized many times before.

This romantic figure, this mysterious man who had abandoned society for the forest, was nothing more than a common thief, stealing blocks of cheese and packages of bacon from little kids.

This is the problem with Finkel's book.

Finkel does his best. His writing is vivid and clear, his reporting is diligent. He is careful not to overstep the journalistic boundaries of what he knows (something that got him in trouble in the past — which he nobly owns up to at the beginning of the book).

Finkel reads all of the literature he can find on hermits and solitude: Thoreau, Edward Abbey, the memoirs of Tibetan Buddhist nuns. He explores the need for aloneness, the damage of solitary confinement. He looks into Asperger's syndrome (just in case Knight is on the spectrum). He consults neuroscientists and psychologists. He woos Knight, writing him letters, visiting him, interviewing him, crashing through the forest himself to find that hidden spot behind those elephant-sized boulders.

His research is comprehensive. And it leads us — nowhere.

There is no big moment when Knight decided to jettison society, no reason that he or anyone else can give for choosing this strange life, no lesson to be learned. Knight can talk all day about how he laid his tarp and killed mice and cased cabins and grew his beard to a precise length in winter to keep warm, but he cannot say why he was out in the woods in the first place.

"Nothing makes complete sense," said Peter Deri, one of the psychologists Finkel consulted. "Knight is like a Rorschach card. He really is an object for everyone to project onto."

Finkel hints at this early on. Someone asked him to find out how Knight coped with the fierce and thick Maine mosquitoes over those 27 summers — surely the hermit had a secret remedy. But when asked, Knight says only, "I used bug spray," and turns away.

There is no wisdom here. Sometimes a hermit is just a hermit. Sometimes a thief is just a thief.

Finkel did his best. The book is interesting, but it is not illuminating.

Laurie Hertzel is the Star Tribune's senior editor for books. On Twitter: @StribBooks On Facebook:

The Stranger in the Woods
By: Michael Finkel.
Publisher: Alfred A. Knopf, 205 pages, $25.95.