Sinclair¹, Sir Clive (Marles) (b. 1940), English electronics engineer and entrepreneur. He founded a research and development company and launched a range of innovative products including pocket calculators and personal computers. A three-wheeled electric car, the C5, failed to achieve commercial success.

Sinclair², Upton (Beall) (1878-1968), American novelist and social reformer. He agitated for social justice in seventy-nine books, including The Jungle (1906) and the eleven-volume 'Lanny Budd' series (1940-53).