Mystic ― The popularity of octopuses was recently on display at Mystic Aquarium as dozens of people who had traveled long distances lined up to have copies of the newly published “Secrets of the Octopus” signed by bestselling author Sy Montgomery.

The octopus enthusiasts had also come to meet co-author Warren K. Carlyle IV, founder of OctoNation, the world’s largest octopus fan club.

Elijah Magnone, 11, came to the aquarium Thursday from Warwick, R.I., with his mother, Joie Magnone, because he, like Carlyle, finds octopuses endlessly fascinating.

“I think the thing that people don’t know about them is that they can fit into whatever size hole their beak will fit in,” he said, explaining that the beak is the only bone in an octopus’s body, which is why they can squeeze through almost any space.

Numerous people told Montgomery that her books have changed their lives, and one woman was so overwhelmed after meeting the authors that she had to sit down with her head between her knees.

Montgomery, the author of 34 books on animal behavior, said many of the questions she had while writing her 2015 best-seller “The Soul of an Octopus," were answered in “Secrets of the Octopus."

National Geographic, which contributed photography, produced a three-part related documentary with James Cameron under the same title, which will premiere on Earth Day.

The book, released March 19, features personal anecdotes, profiles of various species of octopus and a glimpse into the mysterious lives of the creatures that have existed on Earth for 330 million years.

The book also explores octopus social behavior ― from cannibalistic loners to those who live in communal neighborhoods ― and the creatures’ camouflage capabilities.

Octopuses can change their appearance in a fraction of a second to fool predators or prey into thinking they are different creatures, and are so convincing that the animals they pretend to be often can’t tell the difference.

The book also covers intelligence.

“People were amazed that I had written a book called ‘”The Soul of an Octopus,“ because people weren’t ready to admit that octopuses might have consciousness or personality,” Montgomery told the audience.

She said experiments in the early 2010s showed that octopuses ― which are mollusks, an invertebrate group that includes oysters, clams and slugs ― share many hallmarks of intelligence and personality that are seen in humans and other mammals.

“One of them is that they love to play. In fact, they love to play with the same toys our children play with,” Montgomery said. They enjoy taking apart and reassembling Mr. Potato Head toys and Legos, and are great at solving complex puzzles, she said.

Carlyle talked about his journey from founding the non-profit educational organization OctoNation to collaborating on the new book with Montgomery.

He said his initial passion for the animals began as a neurodivergent child who wanted to know everything about the boneless creatures, but his curiosity was stymied by the lack of books available on them.

As an adult, Carlyle was inspired by Montgomery’s writing and ability to make scientific concepts accessible to anyone, with or without a scientific background.

“It empowered me to say, ‘You know what? Somebody has got to change the way people see octopuses,' and I thought, 'That somebody could be me,'" he said.

Today, OctoNation has grown to be the world’s largest octopus fan club with over a million subscribers, and it boasted half a billion views of its content last year alone.

Carlyle wrote a series of “octoprofiles,” for the book containing fascinating details on species such as the mimic octopus, which can replicate the appearance of up to 15 different sea creatures including venomous sea snakes and toxic creatures to deter predators, or the exact color and textured appearance of the ocean bottom.

Despite all the information contained in the book, Montgomery said scientists have only tackled “the tip of the iceberg on octopus research” and still have much to learn about one of the most resilient, curious animals on the planet.