Since its inception, under the will of the dissenting minister Daniel Williams (c.1643–1716), Dr Williams's Library (since the 1860s located in Gordon Square, Bloomsbury, London) has functioned as an exceptional resource for historians of English Protestant Dissent and, in this book, Alan Argent charts the library's own history. The trust's creation was a product of that new-found confidence that characterised English dissenters after the Revolution of 1688 and the passing of the Toleration Act, then confirmed by the Hanoverian Succession and the political dominance of the Whig interest that followed from it. Daniel Williams was determined to provide for the education of dissenting ministers to ensure that they could both serve their congregations resourcefully and answer their adversaries with the confidence that learning might bring. Williams and his first trustees were nothing if not confident about the expansive future of Protestant Dissent, and money was poured out of his trust into charities that would spread the Word, schools in Wales were funded, missionaries despatched to convert native Americans and support offered to Harvard College, Massachusetts. But English dissent in the first half of the eighteenth century was also coloured by Trinitarian disagreements and Dr Williams's Trust was not immune from these tensions: by the mid-century the trustees had adopted Unitarian convictions that would endure for another two centuries.

A chronological approach is deployed by Argent, with the trust's various objects separately discussed within each chapter. He is not uncritical of trustees’ decisions but these are always contextualised. The book is also biographically structured with each chapter built around a principal office-holder, the individuals, clerical and lay, responsible for the management of the trust, from Benjamin Sheppard in the 1720s through to David Wykes in the twenty-first century. An ‘old world’ atmosphere and an inward looking, somewhat exclusive Unitarianism could be said to have characterised the Library until well into the twentieth century. Nevertheless, readers from all backgrounds were drawn to use its rich collections of rare books, manuscripts and portraits that would over time establish Dr Williams's Library as a primary resort for scholars working in dissenting studies as well as those attracted by its holdings in women's history and English literature.

Under David Wykes's directorship, between 1998 and 2021, ‘DWL’ was turned, with the backing of the trustees, into a mainstream research library. Initiatives such as the Centre for Dissenting Studies in partnership with Queen Mary College, the creation of a digital catalogue and databases, the engagement with postgraduate students, the holding of regular symposia and the sponsorship of publications such as of Richard Baxter's five-volume Reliquiae Baxterianae in 2020, were all achievements of Wykes's time in office that offset – and were indeed the fruits of – the controversial sale of the First Folio in 2006. Meanwhile, the library is no longer a Unitarian preserve; trustees are drawn from several denominations, and it is likely that any profession of the Christian faith may soon cease to be required of them. Sadly, publication of Alan Argent's book coincides with the news that the trust and library will be moving out of the Gordon Square, currently for sale for a minimum of £15.5 million. The plan is for the library to be transferred in its entirety to an English university where the trust will fund a librarian and archivist. Crucially, that person and the collection itself will be under university management and control. One can only hope that this upheaval will create a new stability and that ‘DWL’ (which, presumably will remain its title) will retain its status as a major resource for British religious history and more.