He is also a businessman and a Conservative member of the House of Lords. Ridley is best known for his writings on science, the environment, and economics. He has written several science books including The Red Queen: Sex and the Evolution of Human Nature (1994), Genome (1999), The Rational Optimist: How Prosperity Evolves (2010) and The Evolution of Everything: How Ideas Emerge (2015). Ridley was also chairman of the UK bank Northern Rock from 2004 to 2007.