Leonard Kessler, Colorful Children’s Book Author, Dies at 101.

Leonard Kessler, the author and illustrator of hundreds of children’s books for early readers that celebrated the ordinary (“I Have Twenty Teeth — Do You?”) and the not-so-ordinary (“Mr. Pine’s Purple House”), died on Feb. 16 at his home in Sarasota, Fla. He was 101.

His daughter, Kim Kessler, confirmed his death but did not specify a cause.

“A white house is fine,” declared Mr. Pine, the doughty hero of Mr. Kessler’s beloved “Mr. Pine’s Purple House.” “But there are FIFTY white houses all in a line on Vine Street. How can I tell which one is mine?” Mr. Pine then set out to distinguish his house with purple paint, soldiering on despite mishaps and upsets, in a paean to the maverick spirit and perseverance. “Squish, squish, went the brush. Squish, squish, squish.”

When “Mr. Pine’s Purple House” was first published in 1965, the book sold widely for 29 cents a copy. But by the mid-1990s it had been out of print for decades and become a collector’s item, selling for $300 on eBay, as Jill Morgan, a former software engineer, discovered when she tried to find a copy for her own young children.

She tracked down Mr. Kessler, who had retired to Florida and was close to celebrating his 80th birthday, and proposed republishing his work, along with that of other out-of-print children’s book authors.

“I had no experience as a book publisher, but he was all in,” said Ms. Morgan, who in 2000 named her new company Purple House Press in honor of Mr. Kessler, her first author. In the decades since its revival, “Mr. Pine’s Purple House” has remained a best seller for her, Ms. Morgan said.

Jeff Bezos, the Amazon founder, gave the book an another boost in 2014. It had been one of his favorite books growing up, and when he began selling Amazon’s Fire Phone that year, in what would turn out to be a failed attempt to join the smartphone market, he said he had been inspired by Mr. Pine’s adventuresome spirit.

“Certain angels come into your life at the right moment,” Mr. Kessler told The Tampa Bay Times in 2005, speaking of his collaboration with Ms. Morgan. “She gave me back my life again.”

Of the more than 300 books he wrote and illustrated, more than 45 were written with his wife, Ethel Kessler, a social worker and kindergarten teacher.

Mr. Kessler often found inspiration in the everyday. The hungry feelings of a small boy on a trip to the supermarket, for example, are magnified in “Crunch Crunch,” (1955), the sequel to “Plink Plink,” a book about feeling thirsty.

He once told an interviewer that he did a lot of crawling around on the floor to get a child’s perspective on things. When his young son Paul asked him, “Do baby bears sit in chairs?” Mr. Kessler replied, “I don’t know, but that’s a great title for a book.” (“Do Baby Bears Sit in Chairs?” appeared in 1961.)

“The Big Red Bus,” about a bus that lands in a pothole, snarling traffic, was chosen by The New York Times as one of the best illustrated children’s books of 1957. In 1990, it was a Times crossword puzzle clue (“‘Big Red Bus’ Author,” 5 Down).

Leonard Cecil Kessler was born on Oct. 28, 1920, in Akron, Ohio. His father, Albert Lewis Kessler, was a plumber; his mother, Lillian (Rabinowitz) Kessler, was a nursing assistant. Leonard grew up in Pittsburgh, in a neighborhood of European immigrants, and met his future wife, Ethel Gerson, there. They married in 1946, when he returned from World War II. In France and Germany, he had served as an intelligence scout, crawling behind enemy lines after dark to report on its positions, which he delivered in atmospheric sketches.

Planning to be an artist, he attended Pittsburgh’s Carnegie Institute of Technology, now Carnegie Mellon University, on the G.I. Bill, sharing studio space with fellow returning servicemen and a very shy 18-year old named Andy Warhola. After graduating with a B.F.A. in 1949, Mr. Kessler and his wife moved to Manhattan.

A few years later, in 1953, the Kesslers decided to sublet their apartment to Mr. Warhola (who by then had changed his surname to Warhol), who needed a bigger place: His mother, Julia, was coming to live with him, along with her 25 cats, all named Sam.

The Kesslers moved to New City, a town in Rockland County, N.Y. (and into a house they painted pale purple). Mr. Warhol, his mother and the cats all moved into the apartment. But Mr. Kessler kept one room there for his studio and commuted from the suburbs.

Mr. Warhol’s mother was a cheerleader for both artists: “Andy, work! Kessler, work!” was her daily greeting. As for the cats, which she described as “the good Sam … the bad Sam … the crooked eye Sam … the fat Sam,” and so forth, they ended up in a book. Mr. Warhol self-published “25 Cats Name Sam and One Blue Pussy” — his mother did the calligraphy — and gave copies to friends like Mr. Kessler.

In 2006, Mr. Kessler sold his copy, along with a self-portrait that Mr. Warhol had given him, at Sotheby’s, the proceeds from which allowed him to stay in his own home, with care, until his death.

In addition to his daughter, Mr. Kessler is survived by his son, four grandchildren and a sister, Jacqueline Meyer. Ethel Kessler died of Alzheimer’s disease in 2002.

At 80, when he began collaborating with Ms. Morgan, Mr. Kessler bought his first computer, and discovered online shopping, which fed his collector’s itch. In particular, he began collecting his favorite sneakers, Converse, buying them in every hue and pattern, including multiple shades of purple, his favorite color.

“I have a purple door. I have a purple studio,” he told The Tampa Bay Times in 2005. “I think purple is a color that vibrates. I think that’s me.”