William Law was arguably the most influential Anglican theologian of the eighteenth century. The leading Tractarians as well as the Wesleys acknowledged their debt to his Serious call to a devout and holy life. Yet Law remains a comparatively neglected writer. Alan Gregory's account of Law's ‘mystical theology’ is both a description of, and a dialogue with, Law's writings. Gregory is strongest where he deals with the early works, Christian perfection and the Serious call. These works are allowed to speak for themselves, on their own terms (we are thankfully spared the sort of psychoanalysis that was applied to Law in A. Keith Walker's 1973 biography). Law's emphasis on method and rule have been rehabilitated in Christian spirituality in recent years, and are no longer treated with the suspicion that they once were. Gregory's is not simply a work of theological history, however, but also an engagement with Law's thought as a resource for today. In doing so, the author has in places attempted to justify Law's work to a twenty-first century readership, corrected what the author sees as Law's mistakes, and ‘demythologised’ his eighteenth-century worldview. Gregory captures the sense of vitality in Law's writings in contrast to the ‘tedium of deists like Tindal’ (p. 41). Given the flood of recent academic interest in early modern heterodoxy, it is timely to be reminded of how dull many of these deistic works were, and of the wit displayed in the writings of some of their orthodox opponents. Gregory is astute in seeing Law's philosophy, drawn from Boehme, as an attempt to establish an alternative to the Hobbesian philosophy which overshadowed much seventeenth- and eighteenth-century thought. The chapters which deal with the later, mystical works rightly emphasise the continuities with early Law. Indeed, unlike most previous commentators on Law's works, Gregory eschews a chronological treatment and deals, for example, with Law's engagement with Bernard Mandeville in a chapter which deals mainly with the mystical works. The aspects of Law's philosophy borrowed from Jacob Boehme are explained with remarkable clarity. It is suprising, however, that Law's important Letters to the bishop of Bangor on the doctrine of the Church are not even mentioned. This is a useful introduction to William Law. It is however, let down by a very poor index, which includes the improbable entry: ‘Jesus, tendency of, to exaggerate’.