Rutherford played a major role as a reformer at the Westminster Assembly and was also a crucial figure in the establishment of Presbyterianism for Scotland in 1689.

Rutherford's 'Lex Rex' heavily influenced John Locke and in turn, the framers of the US Constitution and Declaration of Independence. Thus Jefferson, Franklin, Madison and Hamilton discussed and formulated their work in the light of the work and opinions of Samuel Rutherford.

Several biographies have been written to eulogise Samuel Rutherford but little has been done to consider the man and his work critically. Kingsley Rendell uses Rutherford's writings and contemporary material to present a comprehensive picture of him from his student days to his death in 1661. Usually described as a model preacher and pastor, Rendell shows he had an even greater ability as an apologist and propagandist.