Kathleen Winsor was born in Olivia, Minnesota and raised in Berkeley, California. She attended the University of California at Berkeley where, at age 17, she married Robert Herwig, a college football star. His senior thesis on King Charles II of England inspired her to read hundreds of books on the subject. She began writing Forever Amber, her first book, in 1940, at the age of 20, and went through numerous drafts of the manuscript. The saga of Amber St. Clare and her romantic adventures in the world of Restoration-era London was nearly 1,000 pages long when it was finally published in 1944. It was an immediate hit with the public and sold 100,000 copies in the first week. It eventually sold more than 3 million copies and was translated into 16 languages. Forever Amber was made into a film directed by Otto Preminger. The runaway bestseller made Kathleen Winsor a wealthy celebrity. She left Herwig and married big-band leader Artie Shaw. She went on to divorce and remarry twice. Kathleen Winsor continued to write but never recaptured the popularity of her first novel.