Harriet Hahn was born in Gatún, Panama, and grew up in Spokane, Washington. After attending Reed College in Portland, Oregon, she graduated from the University of Chicago, where she met her husband, Charles Hahn, with whom she later worked as an editor of the trade magazine he published in Latin America and the Caribbean. Due to Charles’s avid interest in stamp collecting and British postal history, the Hahns traveled frequently to London. On one trip, they stayed at a small hotel that was inhabited by a delightful cat named James, who befriended Harriet and inspired her to write novels about a connoisseur cat.