The 300th anniversary of the publication of Isaac Newton’s Opticks in 1704 provides an occasion to review the history of its composition and publication. As a preliminary to presenting that history, Newton’s attitude to publication and response to criticism are examined. Newton’s clashes with Hooke and his presumed role as the cause of the delay in the publication of the Opticks until after his death are also scrutinized. Rather than simply presenting Newton and Hooke as quarrelsome, which they indeed were, they are presented as rivals to be England’s leading optical authority. Although Newton announced his intention to publish a book very much like the Opticks in the winter of 1675–76, he did not begin to write it until 1687. It was composed in various stages, including new experimental investigations, by 1692, except for the part on diffraction. A planned, but unfulfilled, revision of the part on diffraction was responsible for delaying its publication for a number of years.