In 1922, Burdick earned a two-year degree in business from Syracuse University. He appeared to have stopped collecting in his 20s as he held various jobs, including one in the advertising department at The Syracuse Herald, before landing at Crouse-Hinds, an electronics company in Syracuse.

In his early 30s, he learned he had chronic arthritis, which slowly warped his fingers, stiffened his body and made painful even simple tasks like putting on a jacket. Burdick, who never married or had children, continued to work, assembling small ignitions and fuses, a job he could do while sitting.

His diminished mobility rejuvenated his interest in collecting, which had broadened to include greeting cards, playing cards and valentines. He found solace in the thousands of cards he bought, often for pennies, and he reveled in the stories they told.

“A Card Collection is a magic carpet that takes you away from work-a-day cares to havens of relaxing quietude where you can relive the pleasures and adventures of a past day — brought to life in vivid picture and prose,” Burdick wrote in the introduction to the 1960 edition of the American Card Catalog, which he first published under a different title in 1939.

To streamline and promote the hobby in the early 1930s, Burdick developed the system for classifying cards by manufacturer and type of illustration. Each set or series was given a letter to indicate how or when it was issued, followed by a number.

Using this nomenclature, T206, the most famous set of baseball cards, was issued by a tobacco company in the 20th century. The 200 series designated sports cards, and the low-200s number indicated baseball cards in particular. Early candy and gum cards were assigned an E for early, while postcards were assigned a PC. Other classifications made less sense. Gum cards issued starting in 1933, for example, were labeled with an R.