This study throws new light on the composition of Boyle's Free Enquiry into the Vulgarly Receiv'd Notion of Nature (1686); it also draws more general conclusions about Boyle's methods as an author and his links with his context. Its basis is a careful study of the extant manuscript drafts for the work, and their relationship with the published editions. Section 2 describes Boyle's characteristic method of composition from the late 1650s onwards, involving the dictation of discrete sections of text to amanuenses; it also assesses the effect this had on the structure and presentation of Boyle's writings. Section 3 considers the published text section by section and indicates which parts were written when; it also surveys unpublished draft material relating to the work. Section 4 places the work in context, considering the intellectual threats that Boyle sought to confront in it, both when he initially composed it in the 1660s and when he rewrote it c. 1680. It thus anchors him more precisely than hitherto in the intellectual debates of his day.