Hart's Rules for Compositors and Readers at the University Press, Oxford—today published under the short title New Hart's Rules—is an authoritative reference book and style guide published in England by Oxford University Press (OUP). Hart's Rules originated as a compilation of best practices and standards by Horace Hart over almost three decades during his employment at other printing establishments, but they were first printed as a single broadsheet page for in-house use by the OUP in 1893 while Hart's job was controller of the university press. They were originally intended as a concise style guide for the staff of the OUP, but they developed continuously over the years, were published in 1904, and soon gained wider use as a source for authoritative instructions on typesetting style, grammar, punctuation, and usage.