Maybe you've seen them in your neighborhood – decorated book houses in people's yards that offer a free read to those who pass by.
It got its start in Hudson, Wisconsin, in 2009, when Todd Bol, 59, placed a model of a one-room schoolhouse filled with books in his front yard with a sign that read "free books."
It was a hit with his neighbors.
Bol made a few more of these little libraries and handed them out for free. And now, just five years later, the nonprofit has grown to 25,000 Little Free Libraries in all 50 states and more than 70 countries, according to the nonprofit's website, despite facing some issues with city zoning laws across the country, the Christian Science Monitor reported.
"We're going to pass McDonald's by Thanksgiving," Bol told MPR News. "There's going to be more Little Free Libraries than McDonald's, which is great."
This embed is invalid
With the concept "take a book, return a book," roughly 36 million free books were exchanged by visitors last year alone, Lavender Magazine says. And Little Free Library aims to double its impact by 2017, with a goal of having 50,000 libraries, especially in areas where people have limited access to books.
"We're bringing neighborhoods together through books, literacy and conversation, talking about common goals," Bol told the Pioneer Press. "The (political) right likes us and the left likes us. How do you say 'no' to reading? As a populace, we are upset we are getting pushed apart when we want to come together. That's what Little Free Libraries do."
To celebrate Little Free Library's success and discuss plans for the future, the nonprofit is hosting its first Big Little Party at the Minneapolis Central Library Sunday from 6-9 p.m., KARE 11 reports.
Proceeds from the benefit will go to the Little Free Library, Minneapolis Happening says, to continue its mission of promoting literacy through the global book exchange.
The organization is also celebrating the launch of the The Little Free Library Book, which highlights the people behind the movement, written by Minneapolis-based author and Little Free Library steward Margaret Aldrich.
Little Free Library stewards
The libraries resemble a blend between a birdhouse and a mailbox, the Austin Daily Herald says, and tend to show the personality of the library owner, who is called a steward.
"The personality that people put into their libraries is amazing," Aldrich, who has her own little library, told MPR News. "I've seen Little Free Libraries that look like owls, that look like robots, that look like Victorian mansions. The diversity is just amazing."
Most people build their own libraries, but they can be purchased for anywhere from $300-$1,000 (the nonprofit has tips to help fund a Little Free Library), and then registration in the Little Free Library directory costs about $40, MPR News says.
The nonprofit made $1.5 million in 2014, with 96 percent of income from the sale of little libraries and registration in the directory, the Pioneer Press says.