Deborah MacInnis has worked in libraries since she was in the eighth grade. And the biggest part of that lifetime has been 40 years as children’s librarian at the Edgartown Free Public Library. A self-described flower child of the sixties who found her career by trial and error, she has learned to keep her guiding philosophies pretty simple. She has also learned that when working with children, reality is not a prerequisite.

“There is no such thing as too many dragons,” she said as she searched for just the right book to fulfill a storytime request last Thursday morning. Not just any dragon book would do on this morning.

“I have about 80 million dragon books,” she said. “Oriental dragons are nice. They don’t eat princesses and run around in circles.”

On April 20, from 1 p.m. to 3 p.m., the library will throw a small party to celebrate Mrs. MacInnis’s 40th year of finding dragon books, delighting kids and making the children’s library a fun place to hang out. It has never been boring.

“If you get bored with what you’re doing, you can make up something new,” Mrs. MacInnis said.

Instilling a love of reading and books in children for 40 years. — Mark Lovewell

She said she began her library career because she found it hard to get to school on time.

“I was late for school every single day,” she recalled. “So I would have to stay after for detention. I hate sitting around doing nothing, so I would convince them that I could go work in the library. I would shelve or I would find books or whatever needed doing. I volunteered all the way through high school.”

College at the University of Iowa was an adventure in finding her way, with five changes in her course of study.

“I started out to be a poet,” she said. “In the sixties they were creating art. As long as nobody understands what you’ve done it’s art. You would write something and then you had to muck it up so nobody understood it. I also decided poets could starve.”

After an epiphany of practicality, she graduated from university with a major in elementary education and a minor in sociology. After college she took a job in retail, then worked at the Boston Public Library before applying for a job on Martha’s Vineyard, where her future husband Hugh was a native.

She has never been afraid to try something new. She embraced the fantasy game Dungeons and Dragons, though some parents did not.

“Because there’s no game board, you learn how to really pay attention to words,” Mrs. MacInnis said. “It got them reading all my books on armor, how to build a castle. There are graphic novels now. When I started out you would never have given a child a comic book. It turns out to be really good for kids learning to read. When kids think they’re too old for picture books, graphic novels kind of fill in the space.”

Her long experience is woven with a keen understanding of the scientific and sociological factors that help children get a good start in life.

“Kids who come from a home where parents read to them, go to kindergarten with a 10,000-word oral vocabulary,” she said. “Kids who come from homes with no books, don’t. By the time they graduate from high school, the kids who come from homes where they don’t have this have just gotten to the 10,000 word vocabulary, and the kids who started with that have soared. You don’t have to own books to read to your kids. That’s why they have libraries.”

She finds it gratifying to see a second generation of families coming to her story hour, and she likes to see the kids she once read to who are now police officers, teachers or business owners around town. At the annual town meeting in Edgartown last week Mrs. MacInnis was honored with a round of applause to mark her 40th anniversary. She looked around the meeting and counted how many voters had attended her story hour.

“You’re always in their lives,” she said.

Among her latest passions is a mural planned for the back wall of the library, showing sea life from the oceans around the world, including whales, turtles, sharks, stingrays and a weedy seahorse — which looks like an underwater dragon.

Mrs. MacInnis said after 40 years, she is thinking about slowing down a bit, though any retirement plan will include some work at the library.

For now, she will continue dispensing a librarian’s wisdom. She knows all the short classics to recommend to desperate kids who are behind on their summer reading list. She knows how bathrooms work in castles, and is never at a loss to find a good dragon adventure.

“To be a librarian,” she said, “you don’t have to know anything. But you have to know how to find everything.”