When Leonard S. Marcus wrote his undergraduate honors thesis at Yale University on 19th-century American children's books, he had little sense that he was taking the first step in creating a unique career for himself.
Since Mr. Marcus wrote that thesis 41 years ago, he has carved out a niche for himself as a highly regarded children's book historian, critic and speaker -- someone who is regarded as the ultimate source for providing both perspective and expertise on literature for young readers.
He's written more than 25 books on numerous aspects of children's literature, from a biography for adults, "Margaret Wise Brown: Awakened by the Moon," about the "Goodnight Moon" author, to "Pass It Down," a book for kids about five picture-book-creating families.
Mr. Marcus also has interviewed just about every major figure in American children's books, including Madeleine L'Engle, author of "A Wrinkle in Time," Robert McCloskey, author/illustrator of "Make Way for Ducklings," and Beverly Cleary, author of the "Ramona" and "Henry Huggins" books.
Mr. Marcus' newest book for young readers is "Randolph Caldecott: The Man Who Could Not Stop Drawing" (Farrar Strauss Giroux, $24.99, ages 10-14), a biography of the 19th-century illustrator for whom the Caldecott Medal is named. Now 75 years old, the Caldecott Medal is given annually by the American Library Association to the most distinguished picture book for children.
For adults, the prolific Mr. Marcus served as editor for the just-published "Maurice Sendak: A Celebration of the Artist and His Work" (Abrams, $45), which includes hundreds of previously unpublished artworks by the man regarded as the most important children's book creator of the 20th century.
Over the past few years, Mr. Marcus added "museum curator" to his portfolio. He has curated exhibits at several places, including the Eric Carle Museum of Picture Book Art in Amherst, Mass., and, most recently, at the New York Public Library (NYPL).
The NYPL show, titled "The ABC of It: Why Children's Books Matter," has attracted international attention. In the exhibit, which runs through March 23, Mr. Marcus highlights the place of children's literature in the arts, popular culture and social history through such artifacts as Nathaniel Hawthorne's family copy of "Mother Goose," the original "Winnie the Pooh" stuffed animals and a recording of E.B. White reading from his classic children's novel, "Charlotte's Web."
In a recent telephone interview from his Brooklyn office, Mr. Marcus, who has a history degree from Yale and a poetry degree from the Writers' Workshop at the University of Iowa, reflected on his unusual -- and fulfilling -- job as a children's literature sage.
"I knew, from when I was very young, that language was my medium," he said. "I see myself as a writer, and this is what I happen to write about."
Interestingly, while he says he's always "been very attuned to the sound of words," he struggled to learn to read. Born and raised in Mount Vernon, N.Y., he was the youngest of three children and was labeled a "remedial reader" by a stern kindergarten teacher.
"In a way, I was so into my own world of words that reading was an intrusion," he said.
Mr. Marcus finally mastered reading when his second-grade teacher suggested that he write some poems and then read them to her. Reading what he had written himself was easy and gave him the confidence he needed to finally become a reader.
In high school, he continued to cultivate his innate love of poetry, and also became interested in history.
"I went into college thinking that history was second-best after poetry, which I considered the ultimate way of using words," he said. "I think I was temperamentally suited to being a storyteller."
When he was casting about for ideas for his undergraduate thesis, he remembered his fascination with the way 19th-century intellectuals such as Ralph Waldo Emerson focused on childhood.
Mr. Marcus also discovered that Yale's Beinecke Library had, as he put it, "an extraordinary collection" of children's books of the period, and so he decided to write about the way those books were "signposts of a young nation's emerging values."
Yet Mr. Marcus remained most interested in poetry, and after graduating from Yale, he headed to the University of Iowa and earned a poetry degree. Returning to New York, he found work at Dover Books, where he worked for someone who wrote the introductions to facsimile reprints of children's books of the 18th and 19th centuries.
Mr. Marcus' boss offered him the opportunity to write the introduction to the next book in the series and, he says, "that tied things together for me.
"I saw that I could actually work as a writer in this field that I had studied in college," he said. "From then on, I started looking for opportunities to write about children's books."
He began writing reviews of children's and teen books for The Washington Post and The New York Times, and won a regular gig as the children's book reviewer for the then-new Parenting magazine. He also published his first book about children's literature, the biography of Margaret Wise Brown, and slowly began making a name for himself in children's literature.
These days, Mr. Marcus is much in demand as a speaker, both to librarians and other children's literature experts as well as to kids themselves. He's also working on his next book, for which he plans to interview some of the top graphic novelists working today.
Karen MacPherson, the children's/teen librarian at the Takoma Park, Md., Library, can be reached at Kam.Macpherson@gmail.com.