During his short life William Clifford became renowned not only as a leading mathematician, but also for his philosophy, which embraced the fundamentals of the physical universe, Darwinian evolutionary theory, the nature of consciousness, personal morality and law, and the whole mystery of being. It is now recognised that Dirac's theory of the electron, fundamental to modern physics, is based on Clifford algebra, which is well-known among mathematicians and physicists. He also anticipated Einstein's idea that space is curved. The year after his election to the Royal Society, Clifford married Lucy Lane, a journalist, novelist and playwright. Many well-known scientific, political and artistic personalities attended their salons. After William's death Lucy became a confidante of Henry James . Her wide circle of intellectual friends included Rudyard Kipling, Thomas Hardy, George Eliot, Leslie Stephen, Thomas Huxley, Sir Frederick Macmillan, and Oliver Wendell Holmes Jr. The author has researched the lives of these two influential people from archive material, biographies of those who knew them, and hitherto unpublished collections of letters, giving insight not only into the lives of the Cliffords, but also into the period in which they lived, supplemented by a personal reflection on Clifford's mathematics by Sir Richard Penrose O.M.