This work traces the history of Dr Williams's Trust from the early eighteenth century and concentrates, as it should, on the development of Dr Williams's Library from its genesis as merely one charity among others to its becoming the principal survivor of Daniel Williams's vision. As much as possible, I have attempted to adhere throughout to the chronology of the decisions and events described. An alternative thematic approach would have insufficiently reflected the unequal and uneven stresses placed at different times on the several causes supported by the trust. Nonetheless the trust's various objects have been separately discussed within each chapter.

The main argument here is that Dr Williams's Trust emerged from the situation of Presbyterians in late Stuart London, fearful of threatening Roman Catholicism and disappointed at the rejection of religious comprehension. The trustees’ task was to implement the terms of Daniel Williams's will and over the years to ensure that those causes that had been founded decades, or even centuries, before were upheld. This the trustees have performed faithfully, even when in doing so they and their co-religionists gained little direct benefit. Whether they might have done this better or differently readers may judge for themselves.

My thanks are due to successive trustees, not only for commissioning me to write this history and for affording the facilities to carry out the necessary research, but also for encouragement and patience as the project developed. In addition, I must thank the trust's director 1998–2021, Dr David Wykes, the conservator, Jane Giscombe, and other members of the library staff who have been working through lockdowns caused by the coronavirus pandemic since the spring of 2020. The Jonathan Morgan fund has helped to make this publication possible. If, at times, in my text I appear critical of trust decisions and of the trust's approach, this criticism must be tempered by my respect for those who, over three centuries, have generously and selflessly committed time and energy to the operation of this unique trust, enabling its survival in the twenty-first century. My duty has been to quicken appreciation of the devotion and achievements of the past and thereby to stimulate what might be appropriate responses to the needs of today and of the future.