At his death, Eric Forbes left a collection of the letters of John Flamsteed, the first Astronomer Royal. A leading figure in the final phases of the 17th century scientific revolution, Flamsteed’s extensive correspondence with 129 British and foreign scholars all over the world touches on many of the scientific discussions of the day. This first of three volumes of Flamsteed’s letters acts as a reference to the developments in scientific thinking which occurred during the 17th century. The book is designed to supplement the published correspondence of Isaac Newton and Henry Oldenburg.