John Green, who recalled Amy Krouse Rosenthal Monday as “a brilliant writer, and an even better friend,” credits her with helping him become a top-selling author of young-adult fiction whose books have gone on to be successful movies.

“It’s hard to imagine what my professional life or my personal life would look like without Amy’s influence,” said Green, author of “The Fault in Our Stars,” “Looking for Alaska,” “An Abundance of Katherines” and “Paper Towns.”

“Amy taught me that, for writing to work, it has to be a gift for the reader,” he told the Sun-Times, “rather than an attempt to impress them or an attempt to think you’re cool or whatever.”

Ms. Krouse Rosenthal, whose death Monday at 51 was confirmed by her literary agent, welcomed him to Chicago, invited him to contribute his writings to WBEZ-FM, modeled an inspiring marriage and was “the best gift-giver I’ve ever known,” Green said in an interview days before her death.

While reading her children’s book “Uni the Unicorn” to his daughter Tuesday, he marveled at her originality in creating a unicorn who believed little girls were real.

“I think she’s an actual genius,” he said.

Green was a fan of her writing in “Might,” an influential magazine produced in the 1990s. In 2002, she emailed Booklist magazine, where he worked. He mentioned in his response that he was a “big fan.”

They struck up a correspondence. “One day, she asked me if I had anything two minutes long, good for the radio,” said Green, who was living in Chicago at the time. “I said yes.

“I went back home,” he said, and wrote a piece for WBEZ.

He met Ms. Krouse Rosenthal when he arrived at the radio station. Nervous and excited, he wanted to make sure he was on time. “I got to Navy Pier about four hours early,” he said. “She put me at ease, for sure.

“When we first met, I talked about how I was relatively new to Chicago. My mother and father worried about me in the big city.”

He told her his mother recommended he carry $40 in “mugger money.”

Later, Ms. Krouse Rosenthal “gave me two money clips,” he said. “One said ‘JMG,’ and the other one is ‘MM’ — for ‘mugger money.’ ”

He took part in a 2008 gathering she organized at The Bean in Millennium Park that drew hundreds of her fans — “a magical night,” he said. “You know, I’ve had a few nights in my life that I look back to when I feel sad or scared or alone, and that’s one of them.”

Green and his wife Sarah admired the easy warmth in her marriage to Jason Rosenthal, the subject of her powerful New York Times essay “You may want to marry my husband.”

The piece, written as she was dying of ovarian cancer, envisioned a new, future love for her husband.

“I thought it was vintage Amy Krouse Rosenthal,” Green said. “It was emotionally honest and beautiful and funny and utterly unsentimental and just magnificent and also just gut-wrenching.

“Sarah and I read it and just cried together.”

Green tweeted Monday: “As a parent, a writer, a spouse, and a friend, Amy Krouse Rosenthal was what I wanted to be when I grew up. Her last book, the brilliant ‘Textbook Amy Krouse Rosenthal,’ ended: ‘Bye. I love you. Thank you.’ Goodbye, Amy. I love you. Thank you.”

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CLICK ON VIDEO BELOW to hear John Green talking in 2016 about Amy Krouse Rosenthal