The death of Donald Sobol could be the subject of its own puzzler — “Encyclopedia Brown and the Mystery of Immortality.” Encyclopedia Brown is the hero Sobol created for the series of mysteries via which so many boys, and no doubt some girls, learned not only to read but to grasp the glory of thinking. The newswires are quoting Penguin Books as saying Sobol died last week at the age of 87, more than 60 years after he left the newsroom of The New York Sun, where he’d started out in the 1940s and gained, first as a copy boy and then as a reporter, an early glimpse of how gripping copy can be turned out quickly.

The mystery we find ourselves thinking about on his death is how a man who is himself mortal can create, as Sobol did in the brainy boy detective who noticed so much that he sometimes seemed omniscient, a being who will survive longer than any actual boy born in his author’s lifetime. It isn’t the absence of competing characters. We have, to name but a few Tintin; Dick, Tom, and Sam Rover; Nancy Drew; Frank and Joe Hardy; and Tom Swift. They, too, have survived their authors. It isn’t great skill as a wordsmith, though Sobol was a terrific, straightforward, often witty writer. Nor is it any mastery of the art of, say, the plot, since the ones woven for Leroy “Encyclopdia” Brown were not what one would call Shakespearian.

What was so special about Encyclopedia Brown was the way he drew his courage from his ability to reason, confounding Bugs Meany and his gang at every turn just by observing more and out-thinking his adversaries. When Bugs tried to talk Peter Clinton into trading his bike for a Civil War sword that was engraved to Stonewall Jackson as a gift from the Southern general’s men, Clinton hired Encyclopedia to check the sword’s provenance. Clinton plunked down the Brown’s standard fee of 25 cents. Brown pronounced the sword a fake. How did he know? Jackson’s men would never have engraved a sword as having been presented after the Battle of Bull Run. The southerners knew it as the Battle of Manassas.

It was Encyclopedia who solved the case of the haberdasher who reported that his store had been robbed by Natty Nat. Encyclopedia closed the case over dinner with his parents. His father was the chief of police in Idaville (named for Sobol’s mother) and read his notes on the case at the family dinner table. Mr. Dillon, a partner in the store, said he had been surprised by Natty Nat. When he looked up from the cash register, there was the famous criminal, wearing his signature gray coat with a belt in the back. Natty Nat, gun in hand, ordered Mr. Dillon to turn around and face the wall. When Mr. Dillon finally turned back around, Natty Nat — and the register’s cash — were gone.

Encyclopedia promptly pronounced that there had been no robbery and that Mr. Dillon had stolen his partner’s money by emptying the cash register himself. After all, how could he have known the coat was belted in the back if he’d only seen Natty Nat from the front? This is how Brown bested them. Just by clearer thinking. The fisticuffs were thrown by his partner, Sally Kimball. She once knocked Bugs Meany “flatter than a 15-cent sandwich.” But Encyclopedia could outthink her. One day there was even a contest in which Sally sought to outsmart Encyclopedia by telling the case of the Great Merko. Brown figured it out in a trice. “You told it very cleverly,” Brown condescended, but he deduced that the Great Merko was not a man but a woman.

This is how Donald Sobol lifted young Leroy Brown up to immortality, one delicious deduction at a time, ten stories to a volume, more than two dozen of which were turned out over the decades so that generations of boys could flip to the back of the book to see if they had solved the case correctly. His hero never aged. He never moved away from Idaville. He never betrayed anyone. He had no dark side. He just kept going. Sobol himself, the New York Times notes in its own obituary, never made more than a comfortable, middle-class living from the works, having sold off the broadcast and movie rights early on for a nominal fee. But he enriched the world, and will be doing so for generations to come.