If ever there was going to be an industry that would have nailed down the precise first of its kind, it would be baseball cards. After all, the hobby is practically built upon carefully constructed and scrutinized checklists. The slightest printing errors are cataloged and noted, with differing prices depending on how centered the image is or if a shade of blue isn't quite as cerulean as the next one. The Metropolitan Museum of Art has a large and impressive collection of baseball cards donated by Jefferson Burdick -- a man who essentially put together the very first guide to baseball card collecting and is the forefather of the entire industry.

So, while we know that 1951 was the first year that Topps released a set of baseball cards, and we know Fleer and Goudey helped create the bubble gum card in the 1930s, what was the first baseball card?

That is a little bit harder.

"If you're looking for the Abner Doubleday of baseball cards, you're going to be as frustrated as those who tried to figure out that Abner Doubleday, in fact, didn't invent baseball and he didn't do it in Cooperstown," John Odell, curator and researcher at the National Baseball Hall of Fame, said in a recent phone call.

It's something Odell has thought a lot about. After all, he and the staff at the Hall of Fame spent painstaking hours determining just what is and isn't a baseball card to put into the museum's impressive exhibit devoted to the hobby, Shoebox Treasures.

"So, what is a baseball card? One of the beauties of this is there's no law that says what it is," Odell said.

Fortunately, there's at least a small window in the mid-1800s with roughly three possibilities:

There's the Magnolia Invitation -- though it's actually a game ticket -- for a contest held on Feb. 9, 1844. John Thorn, MLB's official historian, wrote about the voucher in "Baseball in the Garden of Eden."

"It cost a dollar and, given its enamel-coated card stock and its commissioned rather than stock imagery, was likely intended to be saved as a memento of the event. The baseball scene on the card reveals three bases with stakes (not wickets), eight men in the field, a pitcher with an underarm delivery, possibly base stealing, and a top-hatted waiter bearing a tray of refreshments from the Colonnade. ...

"This ticket is the first depiction of men playing baseball in America, and it may also be, depending upon one’s taxonomic convictions, the first baseball card."

The next is a set of cards known as carte de visite (or cdv) featuring the 1866 Lansingburgh Unions -- later known as the Troy Haymakers. Often, these cdvs were made by players looking for a photo of themselves that they could trade or gift to friends and associates, much the way we may have purchased photographic prints after getting our yearbook portraits done in elementary school. These are also the earliest cards listed in Beckett's database, having sold for $25,000 in 2006.

And then there are the series of promotional cards produced by the sporting goods manufacturer Peck and Snyder in 1869, featuring teams like the Mutuals of New York or the Cincinnati Red Stockings. These may have been used as business cards to promote the company, but their appearance and collectibility all share a lot with the humble baseball card. You can even see some of these early cards on display at the Hall of Fame.

But which one is it? Well, it all comes down to how you define a baseball card. While we primarily think of baseball cards as 3 1/2-inch by 2 1/2 pieces of cardboard, the full scope of cards is so much more expansive. Some cards have been printed on metal, wood and fabric. There have been circular cards, diamond-shaped cards and the smaller cigarette cards made most famous by Honus Wagner.

"A couple of things that we came up with [while working on Shoebox Treasures] was: It had to be mass produced. So, then you're getting away from one-offs of people who took the pictures of themselves in baseball regalia," Odell said, referring to cdvs. "You know, 'My name is Johnny Smith, and I love baseball, and I'm living in 1865 and I just got home from the war and I'm going to get a picture of myself taken in my baseball uniform, instead of in my military uniform. I'm not selling it.' That was one of the things that we said -- there needs to be some sort of a commercial aspect to these cards."

Odell also believes there needed to be an expectation that you would enjoy the card and possibly even keep it -- even if nobody was ever planning on keeping one for 100 years in the hopes of one day selling it.

"That's why I would come down very gently on the side of the Peck and Snyder series, because they were using baseball as a way to promote themselves in a similar way that Old Judge did a little bit later on," Odell said.

Thorn disagrees, though he uses much of the same criteria that Odell did. He just believes the card came 25 years earlier.

"For me the first baseball card is indeed the Magnolia invitation of 1844," Thorn wrote in an email. "It is (a) printed, (b) intended for distribution, though only one example survives, and (c) on card stock."

But once again, this is an image of a team, not an individual player. As anyone who has collected cards knows, those are rarely the highly sought-after collectibles that have made baseball card collecting into the juggernaut that it is. Honus Wagner may be the card to get your hands on, but no one is fighting for your team photo card of the 1963 Boston Red Sox.

That's Brian Wentz's argument. Wentz runs BMW Sportscards, a vintage sports cards and memorabilia company, that is currently selling what he believes is the earliest known baseball card set in history with the 1866 Lansingburgh Unions -- later known as the Troy Haymakers. (At times, this has been called an 1870 set, but it features Anthony McQuide, who died in 1867.) Though these were cartes de visite, they were sold commercially by the photographer, E.S. Sterry & Co., through mail order. They may not have been mass produced the way the other cards were, but they were ready to reproduce as many cards as people wanted. These were far more than just gifts and business cards to be given to friends.

Even better, unlike the Magnolia Invitation or the Peck and Snyder cards, you could actually put together a complete team set if you wanted.

"There's six of [the 1866 Lansingburgh Unions cards] that are known, and there's probably going to be nine or possibly 10 in that set. So, that's the first known baseball card," Wentz said. "I've heard other arguments. But, I mean, if it isn't commercially available, if you can't buy it, if you can't assemble a set, it's just a singular item. Those trade cards -- there are a variety of different ones -- they're not really individual player cards. When I think of a baseball card, I don't think of a team card. I think of individual players like Mickey Mantle, Willie Mays, Hank Aaron, Roberto Clemente."

(If you have the money and are looking for the first known complete set in history, BMW Cards is also auctioning the 1866 Rock Island Wapellos set that was likely shot just a few months after the Unions'.)

"Bottom line, can you go out, can you buy 'em and can you put a set together? I think that's the definition of a baseball card set," Wentz said.

While that seems reasonable, Thorn doesn't view the cdvs the same way. He's willing to entertain some of these examples, but in the end, his thinking is clear:

"Interesting subject," he said, "but pre-established criteria must rule, I think, or Newbery's 18th-century illustration comes in."

Fortunately for all of us, we don't need to worry too much. Unless we have plenty of extra cash sitting around, we likely won't ever get a chance to do much more than gaze lovingly at these items behind glass when they're on display. And just like when we were trading cards on the playground, arguing over the trade value of, say, a Tony Gwynn or a Ken Griffey Jr., it's a debate that will never end.

"I think that there's real beauty in somebody saying, 'Well, I think [The Magnolia Invitation] is the first card, and if you don't think so because it's more engraving-y and it's more of baseball as a sport and not as much of a player or a team -- that's fine,'" Odell said. "We can agree to disagree."

Just don't start claiming that your 1960s cereal cards are the first in history and we'll be good.