It's subjective to determine Kristin Hannah's best novel. 'The Four Winds' is highly regarded by many for its exploration of historical themes and strong female protagonist. Different readers have different favorites based on their own interests and emotional connections to the stories.
It's hard to say for sure as it depends on personal preferences. But many consider 'The Nightingale' to be one of her best works due to its powerful story and compelling characters.
The choice of Kristin Hannah's best novel varies from person to person. Some might point to 'The Great Alone' for its vivid descriptions and emotional depth. Others might favor 'Firefly Lane' for its touching friendship tale.