Mary James was the girlfriend and later wife of Atom/Al Pratt. She played a significant but unwitting role in starting his heroic career.

Mary was born to a relatively affluent family. Mary and Al met as students of Calvin College.He was strongly attracted to her, though she hardly noticed him. He approached her one a day in a street corner to negotiate a day. They were interrupted by a mugger. The villain easily defeated the diminutive young man and run away with Mary's purse and jewelry. Pratt was humiliated by his failure to protect the young lady. It inspired him to seek training by Joe Morgan, a former heavyweight boxer who had fallen on hard times.

Months later, the Atom's first case was to rescue Mary James from kidnappers. She was blindfolded and failed to recognize her hero as Al. Later stories had the Atom protecting Mary from jewelry thieves, kidnappers and other villains.

Mary James eventually married Al Pratt. When she became pregnant, she was targeted by the villainous Vandal Savage, who was seeking an infant with metahuman potential for his experiments. Immediately after the birth of her son, one of Savage's minions murdered Mary by smothering her with a pillow, while Savage took the child. Al Pratt was told that both Mary and the baby had died during the delivery.

Mary Pratt's child was infused with DNA from several other metahumans, then turned over to Savage's employee Henry Emerson to raise as his own son. That child, Grant Emerson, eventually grew up to become the superhero Damage.