- Business and economics: Millican is a former business executive and has written several books on business and economics, including "The Lean Startup" and "The Innovator's Dilemma."
- Technology and innovation: Millican has written extensively about the impact of technology and innovation on business and society. His books on these topics include "The Technology Trap" and "The Future of Innovation."
- Creativity and leadership: Millican has written several books on creativity and leadership, including "The Creative Mind" and "The Leadership Challenge."
- Social issues: Millican has also written about a variety of social issues, including climate change, poverty, and inequality. His books on these topics include "The Green New Deal" and "The End of Poverty."
- Personal development: Millican has written several books on personal development, including "The Power of Habit" and "Mindset."
In addition to his books, Millican has also written numerous articles and essays for a variety of publications, including The Wall Street Journal, The New York Times, and The Harvard Business Review. He is a frequent speaker at conferences and workshops around the world.