Irish author Sam McBratney has published dozens of books, but the one with which he is best known, at least on this side of the pond, is book #57, the now-classic Guess How Much I Love You (Candlewick). To celebrate its reissue in a pop-up edition (with illustrations by the original artist, Anita Jeram and paper engineering by Corina Fletcher), McBratney visited the U.S. for the first time in a decade and did a whirlwind tour last month. Stops included visits to the National Book Festival in Washington, D.C. and his publisher’s offices in Somerville, Mass. PW caught up with McBratney and his wife, Maralyn, at Candlewick, where he took time from signing stock.

In honor of the occasion, McBratney, a tall slim man of 68 with impish eyes, sported a silk tie handpainted by illustrator Jeram with the same Nutbrown Hares that are featured in the book. His wife wore a gold necklace with a limited-edition pendant, also of a hare from the book, which she commissioned during the 1995 U.S. tour for Guess How Much I Love You, after it hit bestseller lists. For the record, Maralyn set this reporter straight when she initially inquired about the "rabbit" on her necklace. A hare has longer legs and runs faster. It is also born fully furred and is a different species altogether.

Despite the faux pas, the McBratneys could not have been more gracious if we were meeting in the living room of their home near Belfast, Ireland, rather than a white conference room filled almost entirely by a large table piled with stacks of books. McBratney didn’t seem to mind autographing them for American booksellers, whom he credits with turning Guess How Much I Love You into a mega-seller a year after it launched in the U.K. with a mere 10,000-copy first printing. The story of Little and Big Nutbrown Hare has gone on to sell more than 28 million copies worldwide in 50 languages. According to Maralyn, McBratney’s agent, Gina Pollinger, was one of the first to recognize the book’s potential. At a ceremony for the prestigious Kurt Maschler Award, for which Guess How Much I Love You was shortlisted in 1994, Pollinger saw no reason for McBratney to be downcast for being passed over. "Does he realize he has a bestseller?" she asked.

Not at that moment perhaps, but Guess How Much I Love You did provide another kind of turning point. When McBratney turned 50, shortly after he delivered the manuscript for the book to Walker, Candlewick’s U.K. counterpart, he retired from teaching history after writing only in his spare time. His first attempt, in 1969, was the autobiographical Mark Time, which he describes as “a prepuberty love story.” Like many authors’ first books, he describes the process of getting published as "the usual story of the rejection slip. Stick it in the drawer." Until finally in 1976, it was picked up by Abelard-Schuman. Now more than 40 years later, he would like to republish it.

Although that book was based on his childhood, many of McBratney’s early books were inspired by his children, two sons and a daughter, but now, it’s his grandchildren. As for Guess How Much I Love You, said McBratney, "I’ve never been clear in my mind where the idea came from. "Some books McBratney wrote for himself, like The Chieftain’s Daughter (1993), a historical novel set in the fifth century. "Interest in early Ireland is not rampant in the general public," he pointed out. On the other hand, monsters are. The Lough Neah Monster (1994) about Nessie who comes to visit her cousin monster, was commissioned by Irish publisher O’Brien Press.

As for School Trip to the Stars (1990), it’s one of the few books that McBratney can recall the exact moment when he knew he would write it. "I was standing in the classroom and I saw a star at half three. I thought, wouldn’t that be great to take a school trip up there," he said. "I wrote the heart, for myself, or for a publisher." Growing up during WWII, books were in scarce supply, so he didn’t have many examples from his own youth when he started to write. "There weren’t picture books in Northern Ireland," he said. "There were hardly bananas, much less books."

Since Pollinger’s retirement in 1996, McBratney has acted as his own agent. After becoming a fulltime writer, he said, "I had more time to look into the contracts, and I got to know so many of the editors that I began to send them manuscripts directly." Currently McBratney is working on a quartet of stories about the Nutbrown Hares to complement his four earlier Guess How Much I Love You storybooks from 2007 based on the seasons: In the Snow, Colors Everywhere, A Surprise for the Nutbrown Hares, and When I’m Big. The new stories are about going away and coming home and will be collected in a picture book, Guess How Much I Love You Here, There, and Everywhere, which is due out next fall. "I’m looking forward to these. I love them from the point of view of the artist, in the James Joyce way," he said.

Anita Jeram, the illustrator of Guess How Much I Love You books, lives just three miles from McBratney; he credits her with filling in the details visually in his books. As a writer, he prefers to write very sparsely and avoid lengthy descriptions. "Although in the beginning is the word," said McBratney, "the whole book is a product of the word, the illustrator, and the designer."