Her latest book, "The Valley of Amazement," is being released on Tuesday.
Tan, who was working on another book, saw a picture of her grandmother wearing what appeared to be high-class Chinese courtesan clothing. Though Tan said she doesn't know exactly why her grandmother wore those clothes, she said on "CBS This Morning," "I looked and said, 'What does she really do?' It changes . . . family tales, you know, the woman who was supposedly quiet and old-fashioned traditional."
The photo inspired Tan to research all aspects of the lives of women who worked in "high class" brothels. It inspired her new novel that follows the life of Violet, a biracial girl -- half-Chinese, half-American -- who ends up living in a courtesan house in the early 20th century, and has to come to terms with her Chinese background and her life in the house.
Tan's novel portrays the beauty and the underbelly of courtesan life, but Tan also noted that many other women had it worse on the "continuum of the sex trade."
Tan explained that high-class courtesans "were at the highest level, and it went down to the sex slaves who were just, you know, had a brutal life and died early, died before they were even in their teens.
"Women who were not in these high-class houses were very restricted in what they could do, but you know, in the first class houses they got to get up when they wanted, they got to eat what they wanted. So they were free. They designed their own clothes, they rode out in carriages."
Part of Tan's research for the book also included discovering how the courtesans made sex an art form, but she ran into a few roadblocks along the way: "I couldn't find anything that said exactly what the tricks of the trade were," she said. So her research extended to Chinese pornography from the 1700s.
However, Tan said, at the heart of the book is a story about mothers and daughters, and "the kind of love that we expect from them, but also other people, from men, from children, and also who we are and how we're shaped by our circumstances that are given to us, or by choices we make."
To learn more about Tan's "The Valley of Amazement," visit the HarperCollins website. The book goes on sale Tuesday.
For more with Tan, watch her full "CTM" interview above.