Since he writes Fiction and Non-fiction both, you have to pick out one out of the twos to do the justice to the question.
In total, he has written 16 books to date. His fictions include:
- Pax Indica: India and the World of the 21st Century
- Show Business
- The Great Indian Novel
- The Five Dollar Smile And Other Stories
- An Era of Darkness: The British Empire in India
- India Shastra: Reflections on the Nation in our Time
- India: The Future Is Now
- Shadows Across The Playing Field: 60 Years Of India-Pakistan Cricket
- The Elephant, The Tiger, And the Cell Phone: Reflections on India - the Emerging 21st-Century Power
- Nehru: The Invention of India
- Kerala: God's Own Country
- India: From Midnight to the Millennium and Beyond
- Reasons of State
- Bookless in Baghdad
- Why I am a Hindu
Riot is a great story about the murder of a girl in a riot. I wouldn’t talk much about the plot but it is one of the best novels that you can pick and you won’t regret. Though I feel Shashi Tharoor is very best in writing Non-Fictions as compared to fictions.
His best Non-fiction book is India: From Midnight to the Millennium and Beyond. President Bill Clinton himself had read the book while preparing for his visit to India in 2000.
‘When Tharoor gets down to India as a concrete personal experience, everything seems new and fresh.’ - New York Times on the book.
If you want to know more India, No one can better explain her better than Dr. Shashi Throor. That would summarize my take and views on his works.
Hope it helps.