Interest in Valentine Greatrakes customarily centres on his activities as a faith healer. These reached a peak with a series of well-publicised episodes in 1666, when he travelled from southern Ireland to England. Prominent patients, notably Lady Conway, the blue-stocking confidante of Cambridge Platonists, sought his cures. Greatrakes's career has been explored previously for the light that it may shed on the relationship of traditional and ‘modern’ beliefs, and between older and newer medical therapies. His activities have also encouraged reflection on the philosophy of the early Royal Society and a growth of rationalism. Peter Elmer succinctly summarises older interpretations, and argues that, properly handled, Greatrakes can illumine a variety of questions about politics, society and attitudes in Restoration England and Ireland. Elmer offers the fullest biography, having unearthed fresh information in obscure and unsuspected places. In particular, the initial success of the Greatrakes as planters in early seventeenth-century Ireland is shown and their intimacy with the dominant settler family of the area (the Boyles). At the same time, the vicissitudes encountered by Greatrakes's father, his unhappy death, and Greatrakes's subsequent erasure of them from his own record are emphasised. For the first time, Greatrakes is portrayed as a speculator in and profiteer from the land transfers of the period, and adept at exploiting a network centring on the Boyles which encompassed England as well as Ireland. These connections are represented convincingly as an augury of what was to come in the 1660s. The preliminaries, valuable in themselves, are then used to help explain some of the complexities in Greatrakes's outlook and behaviour. He is placed firmly in the intellectual ambience of his time. Factors are identified that help to explain his favourable reception as a healer in England. In particular, panic over the outbreak of plague in 1665 disposed many to embrace unconventional therapies. Already, there was widespread dissatisfaction with the orthodox practitioners and interest in chemical cures. Elmer also suggests that Greatrakes's support was drawn disproportionately from those who either dissented from the exclusive religious settlement after 1660 or were active in seeking to modify it in favour of a more inclusive one. In some contemporary descriptions Greatrakes's powers parallel those of the Quakers. Greatrakes's ideas are shown sometimes to have resembled those of Benjamin Worsley and Robert Boyle. More generally an overlap between Greatrakes's approach and that of survivors from Samuel Hartlib's circle is argued. Anxiety about healing is also linked with the sense of a disordered or diseased body politic current immediately after Charles ii's restoration. The potentially subversive nature of Greatrakes's stroking – seemingly usurping the king's curative powers – is noted. Greatrakes was reputed to cure all comers regardless of confession, but the author suggests that he was promoted in Ireland, in part at least, as a retort to Catholic miracle-working. In addition, reflections on Greatrakes prompt investigation of ideas about witchcraft. Elmer succeeds in his stated aim of showing that Greatrakes was at the centre, not on the periphery, of the intellectual and political debates of his time. The study adds valuably to understanding of the Hartlib group, the early Royal Society, and the continuing conflicts in England and Ireland over authority in Church and State.