Robert Boyle (1627 91) was the most influential British scientist of the late seventeenth century. His huge archive, which has been at the Royal Society since 1769, has only recently been explored, leading to a new understanding of many aspects of Boyle's thought. This volume brings together the essential materials for understanding the 'Boyle Papers'. It includes a revised version of Michael Hunter's fundamental study of the archive, first published in 1992, which elucidates its history and the way in which handwriting evidence can be used to identify chronological strata within it, thus making it possible to trace the development of Boyle's ideas. Other chapters deal with such components of the Papers as Boyle's 'workdiaries' and his projected Paralipomena; another uses material from the archive to illuminate the making of a key work by Boyle, his 'Free Inquiry into the Vulgarly Received Notion of Nature'; while another illustrates that, large as the archive is, it is only a part of what existed in Boyle's lifetime. Parts of the content have been published before, but they are here presented in revised and fully indexed form. Lastly, the volume includes a completely revised version of the catalogue of the 'Boyle Papers', Letters and ancillary manuscripts originally published in 1992, updating it by tabulating the extensive use of the archive made in recent years in connection with the publication of the definitive editions of 'Boyle's Works and Correspondence' (1999 2001). In all, the volume will be indispensable to anyone with a serious interest in Boyle.