(Washington Post) - Amy Krouse Rosenthal, who wrote unconventional memoirs and whimsical children's books that became bestsellers and whose final project was a moving love letter - in the guise of a dating website profile - to her soon-to-be-widowed husband, died on March 13 (Monday) at her home in Chicago. She was 51.

The cause was ovarian cancer, which had been diagnosed in 2015 and was confirmed in a statement by her literary agent Amy Rennert.

Rosenthal's essay You May Want To Marry My Husband, was published online in the New York Times on March 3 and in the newspaper's print edition two days later."I need to say this (and say it right)," she wrote, "while I have a) your attention, and b) a pulse.

"I have been married to the most extraordinary man for 26 years. I was planning on at least another 26 together." Describing the things they would never be able to do together, she said they moved on to "Plan 'Be'", or enjoying the moment at hand and the times shared with their three children.

"He is an easy man to fall in love with," she wrote about her husband, Jason Rosenthal. "I did it in one day." She continued: "I probably have only a few days left being a person on this planet. So why I am doing this?

"I am wrapping this up on Valentine's Day, and the most genuine, non-vase-oriented gift I can hope for is that the right person reads this, finds Jason, and another love story begins."

The essay has been read, according to the Times, by almost 4.5 million people.

Before that story, Rosenthal was best known as a prolific author of quirky children's books, which often viewed the world in unexpected, inside-out ways. She published almost 30 books for children and reportedly had completed seven more before her death.

Her books, which were illustrated by several artists, included Spoon, in which a spoon envies the exciting lives led by other kitchen utensils.

"You know, Spoon - I wonder if you realise just how lucky you are," Spoon's mother says. "Your friends will never know the joy of diving headfirst into a bowl of ice cream. They'll never know what it feels like to clink against the side of a cereal bowl. They'll never be able to twirl around in a mug, or relax in a hot cup of tea."

Rosenthal's other children's titles included Uni The Unicorn, which takes place in a world in which a unicorn imagines that little girls - considered figments of the imagination - are real.

Duck! Rabbit! is built on a simple illustration by Tom Lichtenheld that can be interpreted as either a duck (looking left) or a rabbit (looking right).

Little Oink is about a well-dressed pig who hates messes: "All my friends get to clean their rooms. Why can't I?"

Little Pea tells the story of a pea whose parents make him eat candy before he can enjoy a dessert of spinach.

"Her books radiate fun the way tulips radiate spring: they are elegant and spirit-lifting," author Bruce Handy wrote in the New York Times Book Review in 2009. "Better yet, her jokes sing with specificity and an understanding of children."

Rosenthal also published two volumes of memoirs - one in the format of an encyclopedia, the other as if it were a textbook.

"We were driving past the hospital once, and my mom said, 'That's where you were born,' " she wrote under the entry What My Friends Were Confused By As Children in Encyclopedia Of An Ordinary Life (2005). "I thought she was pointing at the phone booth on the corner, so for the longest time, whenever I saw someone enter a phone booth, I thought they were going to come out with a baby."

Amy Renee Krouse was born April 29, 1965, in Chicago. Her parents were publishers of educational and reference books.

She graduated in 1987 from Tufts University in Medford, Massachusetts, and spent nine years working in advertising before deciding to pursue her own writing projects in what she described as a "McEpiphany", while sitting in a McDonald's with her children.

In addition to her husband, of Chicago, survivors include their children; her parents, Paul and Ann Krouse of Lake Forest, Illinois; two sisters; and a brother.

Besides her books, Rosenthal was a radio commentator, a magazine contributor and a speaker at TED talks conclaves - for technology, education and design. She also embarked on a number of endeavours that defied classification. She once pinned 100 US$1 bills to a tree. She left notes for users of ATMs, which she called "Always Trust Magic". She left copies of her books in taxis or, in one case, concealed inside a snowman, then asked the future readers to get in touch with her.

After writing her first memoir, she took a polygraph test with questions she wrote herself, including, "Is what you've written in this book the truth as you know it?" and "Did you write this book to the best of your ability?" She passed the polygraph.

Rosenthal also made several short films, including the sweetly personal 17 Things I Made, which included some of her books, her children, a peanut butter-and-jelly sandwich and her marriage vows.

The film concluded with an open invitation to meet her at 8.08pm on Aug 8, 2008, at Chicago's Millennium Park. Hundreds of people came out.

Beginning with the statement to "make a grand entrance", Rosenthal gave instructions to people, each building off the word "make". She gave a bouquet of flowers to a man to hand to a stranger as a way to "make someone's day". After the command to "make a splash", children ran through a fountain.

For the next three years - on 9/9/09, 10/10/10 and 11/11/11 - Rosenthal held gatherings at the same spot, which came to be collectively known as The Beckoning Of Lovely. The final instruction before she sent people out into the world was "Make the most of your time here."