Mr. Hill’s books about the yellow dog Spot sold more than 60 million copies. (Courtesy of Penguin Young Readers Group)

Eric Hill, the children’s author who enlivened story time and bedtime for millions of youngsters with his simply told, lift-the-flap tales of the yellow dog Spot, died June 6 at his home in Templeton, Calif. He was 86.

The Penguin Young Readers Group, Mr. Hill’s American publisher, confirmed but released no other details of his death.

A puppy of indeterminate breed and seemingly universal appeal, Spot first bounded onto children’s bookshelves in England, Mr. Hill’s native country, with the publication in 1980 of the book “Where’s Spot?”

With brightly colored illustrations by the author, the volume was released later that year in the United States and grew into a series that sold more than 60 million copies. Few children came of age in the past three decades without meeting Spot or encountering his franchise, which included extensive merchandising and a popular animated program.

Among preschoolers and the grown-ups who read aloud to them, Mr. Hill was widely beloved for the timeless canine character he had created. In the more specialized circle of publishing executives, he was credited with popularizing the use in children’s literature of the paper flap, a physical device used to maximize delight and surprise.

Eric Hill, creator of the yellow dog Spot, died June 6 at 86. (Courtesy of Penguin Young Readers Group)

“That Spot! He hasn’t eaten his supper. Where can he be?” millions of parents have read to their children, perhaps more than once. “Is he behind the door?”

No, he is not, the little ones discover, as they open a blue paper portal to find, somewhat incongruously, a bear eating honey.

“Is he in the piano?” reads another page.

Spot is not there either, children find, when they open the lid of a hot pink baby grand to find a hippopotamus resting atop the soundboard.

Mr. Hill stumbled on the conceit in the late 1970s, when he was working in England as a freelance illustrator. His young son became enthralled with one of his projects, an advertising flier that featured a flap.

“I showed him a funny drawing of a man with a bowler hat on, but the arms were the flaps so he could actually remove the hat from his head,” Mr. Hill once told an interviewer. “A great big smile appeared on Christopher’s face and he said, ‘Do it again!’ ”

For his son’s entertainment, Mr. Hill created a lift-the-flap book about a puppy in search of a ball, according to accounts of the birth of Spot. An acquaintance introduced him to a literary agent, who correctly discerned commercial potential.

“Who and where is Spot — and who cares anyway?” read a New York Times review in 1980. “To answer the last question first: Beginning lookers and readers will care because the book has bold, colorful illustrations, simple, almost repetitive questions in large type and some amusing surprises. . . . Pages and flaps are sturdy and durable enough for little hands to do many re-searches.”

After the publication of the first Spot book, Mr. Hill found a demand for more. “I got letters from readers who said I just couldn’t leave Spot in a basket,” he recalled, referring to the hiding place revealed at the end. “It became a whole new life for me.”

Later titles included “Spot Goes to the Park,” “Spot Goes to School,” “Spot’s First Words,” “Spot’s Favorite Colors,” “Spot on the Move” and “Spot Says Please.”

“Everything happened in a natural progression,” Mr. Hill said. “Spot went for a walk, then it seemed natural that he’d have a birthday. Then people asked about Spot’s father. Well, Spot’s father is a working dog, so he didn’t appear until Spot was ready to go on holiday.”

Mr. Hill considered himself an illustrator foremost and took pride in his uncluttered pages. Even their fanciest element — the flap — was more staid than the pop-ups that other authors preferred.

“I’m not over-enamored of complicated books,” he said, according to the Daily Telegraph, “and wonder if it’s more for the author’s ego than anything else?”

Children endorsed his literary decisions when, upon locating Spot in his wicker hideaway, they demanded to start the search again.

Mr. Hill was born Sept. 7, 1927, in north London. He spent part of World War II in the countryside and later returned to the city, where he worked as a messenger at an illustration studio. He had developed a particular interest in drawing planes.

“As a child, during the war, I drew Spitfires and Messerschmitts,” he recalled, according to the Sunday Tasmanian of Australia. “With Spot, I found that I had designed a fuselage! His spot is on his side, the roundel marking of an English fighter plane, and the color bar of his tail is the color stripes of a plane’s rudder.”

Mr. Hill served in the Royal Air Force during the war. Early in his career, he worked for a period as a cartoonist and sold his work to publications including the magazine Lilliput, according to a biographical sketch on the Penguin Web site. He moved to the United States in the 1980s, living first in Arizona and later in California.

He was married twice and had two children. A complete list of survivors could not be confirmed.

Mr. Hill once explained why his books might have been comforting to the young, even if they would not understand the reason until they were much older.

“There is no violence in the books. No pussycats get chased,” Mr. Hill observed. “Spot is a green character, he likes nature and has a tendency to be a vegetarian. He is a happy dog, a little naughty at times, but predictable.”

He added, “Children like this.”