When Stephen Mullins was in summer camp and sent his mother six ceramic drinking jugs he bought for $1 apiece, he didn't anticipate that that single gesture hinted at a lifelong pursuit.

That was 1947. Seventy-one years later, Mullins displays more than 8,000 of the jugs at the American Toby Jug Museum in Evanston, Ill., just north of Chicago. The jugs, some dating to the 18th century and other as recent as the Black Panther film, are commonly referred to as Toby jugs.

The name, some have suggested, is either a reference to Sir Toby Belch, the jolly drunkard in Shakespeare's Twelfth Night, or to the character in an 1871 English drinking song championing the fictional Toby Fillpot, whose indulgence in alcohol turned his frame into a permanent drinking vessel.

Whatever the truth, the mugs have endured for centuries. The earliest jugs depict a jovial British everyman, usually holding a mug of beer and topped by a tricorn hat that serves as the jug’s spout. Whereas Toby jugs depict the full body of the person, jugs forming just the bust of a person are known as “character jugs.” Mullins' museum features both.

His is the largest public collection in the world, featuring more than those even in Stoke-on-Trent in Staffordshire, England, where easy access to clay, coal, and other ingredients in the mid-1700s led to a revolution in pottery manufacturing. The earliest Toby jugs can be traced there; the Evanston museum has about 200 jugs from that period as well as others made throughout the world.

The museum, which has free admission, is overwhelming at first. Rows of glass cabinets line the floor holding jugs from different centuries. There are terra cotta and ceramic representations of pirates, mystical creatures, Dickens characters, British prime ministers, American presidents, movie stars and starlets, and even Looney Toons and Marvel characters, from Daffy Duck to Spider-Man.

Mullins, a real estate investor and developer, built the six-story complex where the museum is located. He opened it in 2005 after moving his growing collection from his home to his downtown Evanston office to the back of a collectibles shop.

The museum, now a public nonprofit entity, attracts about 3,000 people each year, many of them collectors. Besides his hobby of collecting, there are also the books he writes: He and co-author David Fastenau have written three volumes, which they continue to update, on the history of the jugs.

Mullins started collecting almost immediately after that fateful summer as a teenager. As a college student driving to Dartmouth from Chicago’s North Shore each semester, he commonly visited small-town china shops, where he pulled dusty Toby jugs off the shelves and sent them home to his mother. More arrived packed in a steamer trunk after he was stationed in Germany with the U.S. Army. By then, his patient mother counted 100 jugs that her son sent home in her name. It was time to have a talk.

"She acknowledged that maybe this was my collection and not hers," he said.

Mullins kept collecting throughout his professional life, and by 1999, he had amassed 4,000 jugs, which he stored for display in custom-built glass cabinets in his office. His obsession, he says, is not grounded in anything more than simple intrigue and a gene for collecting.

"There's something fascinating in the faces," he says.

They are also compact, unlike antique cars he started collecting, then abandoned when he realized the hobby wasn't practical.

"I knew myself too well, so I just concentrated on this one thing," he says.

In search of jugs, he has traveled from small towns across the Midwest to places all over the world, including in Australia, New Zealand, and South Africa. Today, the surest way to find them is eBay.

Jamie Doerr, the senior research director at M.S. Rau Antiques in New Orleans, one of the oldest antiques business in North America, says Toby jugs appeal to certain collectors because of the workmanship. But their mystery is also a strong attraction, considering that "nobody can agree on how they originated or who came up with them first."

The museum is open Wednesdays to Fridays, plus two Saturdays a month. Because admission is free, the museum is sustained largely through the online sale of duplicate Toby jugs that are stored in a back room.

When Mullins is in town, he says, he likes to watch people enter through the front doors and, as they turn the corner, see their eyes widen when they see the first of 100 display cabinets. "They have no idea what they are coming into. I like to think they're about to have a one-of-a-kind experience," he says.

Now 86, he has already made plans for the museum to continue showcasing his "lifetime love" when he's gone. Some associates, such as assistant curator Sandra Lachler, have agreed to continue the museum's mission.

As for those original 100 or so jugs he sent home to his mother, they remain on display in a special place: his home.

"Although we have duplicates of each one at the museum," he adds.

American Toby Jug Museum: tobyjugmuseum.com