In the glory days of '50s baseball cards, the trade value was on the front but the magic was on the back.

In the days when Googling a baseball question meant opening a shoebox under your bed, the back of the card brought you stats, stories, and cartoons in a distinctive, heroic style.

George Sosnak took it one better. He inked that magic directly onto baseballs. He tranformed a style into an art form all his own. His work now transcends memorabilia. It's a uniquely American form of folk art.

Sosnak spent decades as a baseball umpire, and if you are living the baseball life, you have a lot of down time. While waiting to work a minor league game in Idaho in 1956, he was asked by a female fan if he could paint her favorite player on a baseball. The amateur painter said yes and the rest is history. He gave her the baseball as a gift. He went on to paint, and give away, hundreds more.

Over time his reputation spread, and he mixed commissioned baseballs with projects of his own. In many cases he would start with a star's signature, then build his design around it. He memorialized great moments and championship teams, but he also recorded oddities and trivia. There's a Sosnak ball on the player who was traded for a candy bar. There's one for Johnny Mostil, by legend the only center fielder to ever register an out by catching a foul ball.

Experts have pored over his life and work since his death in 1992, and above all else there's this: Sosnak painted because he loved baseball. He painted because he was happy to oblige. It wasn't about making a living as a painter; his off-season jobs ranged from donut maker to construction worker. He never officially made it to the bigs as an umpire, but from his home in Lakeland, Fla. he umpired spring training games for the Detroit Tigers.

Legendary Tigers manager Sparky Anderson acknowledged both sides of Sosnak's career in a quote that would have made him proud. "He did the most wonderful job of hand-painting a baseball. He was the best I've ever seen at doing his job. He also did a good job of umpiring."

In addition to baseballs (roughly 3,000 started and an estimated 800 finished) he completed a number of two-dimensional works, too, including a poster that's now in the collection of the National Baseball Hall of Fame. Professional Baseball Centennial, 1869-1969, features club and league logos and even the artist's signature whimsical player portraits. Sosnak donated the poster to the Cooperstown, N.Y. institution in 1973, and the hall has graciously lent it to this exhibition.

Towards the end, the man who could turn a baseball into a humorous sort of round mural set out to paint a baseball for every player in the Hall of Fame. Today, they are some of his most sought-after balls by collectors. He didn't complete the project, but we are pleased that his Willie Mays Hall of Fame ball is part of this exhibition.