I've just finished the book
The book is so remarkably different that it's a credit to Wilder that he came up with the story in the movie!
The book was titled "Ariane" by Claude Anet (famous for having written a best-selling account of Mayerling) and written in 1924. Though the author is French, the book is set in Russia at some time apparently years before the Russian Revolution (we don't know when).
She goes from 16 to 18 years old in the book, a widower's daughter - but doesn't live with father at all, but with her aunt - until she decides to sleep with her aunt's married boyfriend - and is then expelled from the house and sent away to university.
Ariane is a true femme fatale, driving men crazy with her coolness - eagerly taking money from some as a mistress but nevertheless breaking their hearts with her frank and scathing assessments of them. She breaks all the "rules of love" these older men have (e.g., she refers to others she's seeing simultaneously, refers frequently to her romantic past, assesses her lovers' good and bad points, says easily that she's indifferent to the lover and fortunately beyond any question of love).
She refuses to play any game of counterfeit emotion, admiration, affection - she's in it for the dough.
Much of the book takes place in Moscow where she lives with one of her much older sugar daddies - she's highly promiscuous and she does drive him crazy.The story is mainly told from the point of view of the man for whom she's the mistress - who is driven mad by her tough coolness.
The movie is MUCH more innocent! Essentially the serious aspects of this character in the book are made fictitious and humorous in the movie.