A CAMBRIDGE, MASS., NEIGHBOR ONCE asked Hans Rey how he survived life with his strong-willed wife, Margret, cocreator of the Curious George children's books. Easy, replied the soft-spoken Hans. "Years ago, we decided that I make all the big decisions and she makes the small decisions. So far in our marriage, there haven't been any big decisions."

As an illustrator, Hans gave the trouble-prone George his mischievous look. But it was author Margret, who died on Dec. 21 at 90 following a heart attack, who endowed George with his irrepressible soul—having him blithely wreak havoc one moment, before saving the day in the next. Barely 5 feet tall, Rey posed as a human model for her husband's simian paintings, scrunching up her face and even jumping from chair to chair. "She was always unpredictable and doing things creatively," says Nader Darehshori of Houghton Mifflin, publisher of the series since 1941. "Often, I thought she was Curious George."

Born in Hamburg, Rey, the daughter of a German Parliament member, and her husband were living in Paris when a publisher asked them to write a children's book. When the Nazis invaded a year later, in 1940, the two fled by bicycle with their unsold manuscript and drawings stuffed in their pockets.

After Hans's death in 1977, Margret devoted herself to their only offspring—Curious George. With a new collaborator, she churned out 28 books and licensed the monkey's image for dolls and a TV show. She was inspired, it seemed, less by the money than by a romantic attachment to her late husband. Says Darehshori: "She looked at George as something special to both of them."