Washington writer Bill Adler Jr. was rejected by 20 publishers before he found one willing to put out "Outwitting Squirrels,” a book about defeating the birdseed-stealing rodents. . (Courtesy Bill Adler Jr.)

It is a testament to writer Bill Adler Jr.’s persistence that even after 20 publishers rejected his book proposal, he never gave up. He was as determined to get his book into print as a squirrel trying to break into a “squirrel-proof” bird feeder.

That’s fitting, as the book that was finally accepted by the 21st publisher was called “Outwitting Squirrels: 101 Cunning Stratagems to Reduce Dramatically the Egregious Misappropriation of Seed From Your Birdfeeder by Squirrels.”

“I can’t blame the publishers for rejecting ‘Outwitting Squirrels,’ because most of the houses I sent my proposal to were in New York,” Adler wrote in an email from Japan, where he now lives. Book editors in New York City, he said, couldn’t understand why anyone would want to feed birds.

“I was lucky the editor at Chicago Review Press I sent the proposal to fed birds,” Adler wrote. “She understood and loved the proposal.”

Since the book’s publication in 1988, there have been three editions of “Outwitting Squirrels.” Together, they’ve sold more than 900,000 copies. Not bad for an idea that came to Adler when he was enraged.

I knew Bill back in the mid-80s. We were both active in the Washington freelance writer community. At the time, he was living in a one-bedroom apartment in the District’s Woodley Park neighborhood, devoted to a solitary profession and starved of the sort of companionship that a pet might have provided. His building didn’t allow them.

And so Adler suction-cupped a bird feeder to the outside of his living-room window. He welcomed his feathered friends — cardinals, finches, chickadees. He did not welcome his furry enemies. It didn’t take long for squirrels to start partaking of the feast.

“Not just at the feeder, but in the feeder, laying in it like the feeder was a sofa, eating all the birdseed,” he wrote me.

When Adler banged on the window, the squirrel would flee. But could he really drop everything to guard his precious seeds around the clock?

And so he began to study the squirrels’ behavior closely. He noticed they jumped from an air-conditioning unit, then climbed up a brick wall to the feeder. He sprayed a slick Teflon coating on the wall so they couldn’t get a paw-hold, then arranged empty Perrier bottles on the AC box.

When they defeated those measures, Adler bought a different feeder, customizing it by hammering nails — points up — through its wooden roof.

He embarked on an arms race — and realized that in his struggle, there was a book.

It was a project he preferred to keep to himself.

“You have to understand, I was single and dating at the time,” Adler, 59, wrote. “Or trying to date. Who would want to go out with a guy who’s writing a book about squirrels? Not just writing a book, but spending lots of time with squirrels, especially early in the morning when squirrels are active, so I could observe them.”

Adler’s book is as much about attracting birds as outwitting squirrels. He compares various feeders, rating them on such features as attractiveness, ease of filling and squirrel-proofness.

It’s doubtful, he said, whether any feeder can be 100 percent impervious to squirrels. “Squirrels have nothing to do all day long but try to figure out how to break into feeders,” he wrote. “They’re not just clever, but determined and relentless. Like Jaws or the Terminator, they won’t ever give up.”

The book found an audience, as Adler knew it would.

“People like to know that they’re not alone in their misery,” he wrote. “ ‘Outwitting Squirrels’ shows readers that no matter how bad your problem with squirrels is, somebody else has it worse.”

Four years ago, Adler moved to Tokyo. He said he’s never seen a wild squirrel in that city. “It’s not like they’re outlawed here,” he wrote. “People in Tokyo rarely feed birds and that may be the reason squirrels don’t hang out in town.”

But the apartment he shares with his rescue cat, Kinmo, is just 20 minutes from one of the “squirrel zoos” that are not uncommon in Japan. It has an exhibit on his nemesis, the American gray squirrel.

“I nearly fell to my knees in laughter when I saw that,” he wrote. “It’s a big exhibit, too, with a long, curving tunnel the squirrels can run and play in.”

Adler has authored more than 20 books, from novels to guides based on “Outwitting Squirrels”:“Outwitting Deer,” “Outwitting Mice” and “Outwitting Contractors.” His squirrel book has outperformed them all.

And in the 30 years since its publication, Adler has altered his thinking a bit: “I now think people should put out two feeders — one for birds and one for squirrels.”

Anti-squirrel measures in a nutshell

Debi Klein of the Backyard Naturalist in Olney, Md., said the best way to safeguard a feeder is to position it 10 feet from any feature — a tree, an eave, a fence — that a squirrel can jump from. Then mount a baffle on a pole or chain to block access. The best feeders are designed to shut when anything heavier than a bird lands on them. Good luck!

Test your squirrel knowledge

How well do you know squirrels? To take my online Squirrel Week quiz, go to washpost.com/johnkelly.

Twitter: @johnkelly

For previous columns, visit washingtonpost.com/people/john-kelly.