John Stuart Mill in his “Autobiography” declares with truth that “the world would be astonished if it knew how great a proportion of its brightest ornaments, of those most distinguished even in popular estimation for wisdom and virtue are complete sceptics in religion.” Many of these, as Mill points out, refrain from various motives from speaking out. The work I have undertaken will, I trust, do something to show how many of the world’s worthiest men and women have been Freethinkers.

My Dictionary does not pretend to be a complete list of those who have rendered services to Freethought. To form such a compilation would rather be the task of an international society than of an individual. Moreover details concerning many worthy workers are now inaccessible. Freethought boasts its noble army of martyrs of whom the world was not worthy, and who paid the penalty of their freedom in prison or at the stake. Some of the names of these are only known by the vituperation of their adversaries. I have done my best to preserve some trustworthy record of as many as possible.

The only complete work with a similar design of which I have any knowledge, is the Dictionnaire des AthÉes anciens et modernes, by Sylvain MarÉchal with its supplements by Jerome de Lalande the Astronomer, An. VIII. (1800)–1805. That work, which is now extremely rare, gave scarcely any biographical details, and unfortunately followed previous orthodox atheographers, such as Buddeus, Reimmann, Hardouin, Garasse, Mersenne, in classing as Atheists those to whom the title was inapplicable. I have taken no names from these sources without examining the evidence.

A work was issued by Richard Carlile in 1826, entitled A Dictionary of Modern Anti-Superstionists; or, “an account, arranged alphabetically, of those who, whether called Atheists, Sceptics, Latitudinarians, Religious Reformers, or etc., have during the last ten centuries contributed towards the diminution of superstition. Compiled by a searcher after Truth.” The compiler, as I have reason to know, was Julian Hibbert, who brought to his task adequate scholarship and leisure. It was, however, conceived on too extensive a scale, and in 128 pages, all that was issued, it only reached to the name of Annet. Julian Hibbert also compiled chronological tables of English Freethinkers, which were published in the Reasoner for 1855.

Of the Anti-Trinitarian Biography of the Rev. Robert Wallace, or of the previous compilations of Saudius and Bock, I have made but little use. To include the names of all who reject some of the Christian dogmas was quite beside my purpose, though I have included those of early Unitarians and Universalists who, I conceive, exhibited the true spirit of free inquiry in the face of persecution. To the Freydenker Lexikon of J. A. Trinius (1759) my obligations are slight, but should be acknowledged. To Bayle’s Dictionary, Hoefer’s Nouvelle Biographie Generale, Meyer’s Konversations Lexikon, Franck’s Dictionnaire des Sciences Philosophiques, and to Larousse’s Grand Dictionnaire Universel I must also express my indebtedness. In the case of disputed dates I have usually found Haydn’s Dictionary of Biography (1886) most trustworthy, but I have also consulted Oettinger’s valuable Moniteur des Dates.

The particulars have in all cases been drawn from the best available sources. I have not attempted to give a full view of any of the lives dealt with, but merely sought to give some idea of their services and relation to Freethought. Nor have I enumerated the whole of the works of authors who have often dealt with a variety of subjects. As full a list as is feasible has, however, been given of their distinctive Freethought works; and the book will, I hope, be useful to anyone wishing information as to the bibliography of Freethought. The only work of a bibliographical kind is the Guide du Libre Penseur, by M. Alfred VerliÈre, but his list is very far from complete even of the French authors, with whom it is almost entirely occupied. I should also mention La Lorgnette Philosophique, by M. Paquet, as giving lively sketches, though not biographies, of some modern French Freethinkers.

In the compilation of my list of names I have received assistance from my friends, Mr. G. W. Foote (to whom I am also indebted for the opportunity of publication), Mr. W. J. Birch, Mr. E. Truelove and Mr. F. Malibran. For particulars in regard to some English Freethinkers I am indebted to Mr. Charles Bradlaugh, Mr. George Jacob Holyoake and Mr. E. T. Craig, while Professor Dalla Volta, of Florence, has kindly assisted me with some of the Italian names. I must also express my indebtedness to A. de Gubernatis, whose Dizionario Biografico degli Scrittori Contemporanei I have found of considerable service. My thanks are also due to G. K. Fortescue, Esq., for permission to examine the titles of all Freethought works in the British Museum.

Some readers may think my list contains names better omitted, while omitting others well deserving a place. I have, for instance, omitted many foreign Liberal Protestants while including Bishop Colenso, who, ostensibly, did not go so far. But my justification, if any, must be found in my purpose, which is to record the names of those who have contributed in their generation to the advance of Freethought. No one can be more conscious of the imperfections of my work than myself, but I console myself with the reflection of Plato, that “though it be the merit of a good huntsman to find game in a wide wood, it is no discredit if he do not find it all”; and the hope that what I have attempted some other will complete.

The most onerous part of my task has been the examination of the claims of some thousand names, mostly foreign, which find no place in this dictionary. But the work throughout has been a labor of love. I designed it as my humble contribution to the cause of Freethought, and leave it with the hope that it will contribute towards the history of “the good old cause”; a history which has yet to be written, and for which, perhaps, the time is not yet ripe.

Should this volume be received with an encouraging share of favor, I hope to follow it with a History of Freethought in England, for which I have long been collecting materials.