The world can doubtless never be well known by theory: practice is absolutely necessary; but surely it is of great use to a young man, before he sets out for that country, full of mazes, windings, and turnings, to have at least a general map of it, made by some experienced traveller.
Philip Dormer Stanhope, 4th Earl Chesterfield (1694–1773), British statesman, man of letters. repr. in The Letters of the Earl of Chesterfield to His Son, vol. 1, no. 190, ed. Charles Strachey (1901). letter, Aug. 30, 1749 (first published 1774).