This second volume of the Acton–Simpson correspondence contains 267 letters, from September 1859 through June 1862. This covers the period of Acton's editorship of the Rambler until its transformation into the Home and Foreign Review. This was the period of the most intense correspondence between the two men. The remaining letters, through 1875, will appear in Volume III, along with a bibliography.

A third editor has been added for these two volumes. Professor James C. Holland of Shepherd College is a former student of Father McElrath and collaborated with him in the publication of Lord Acton: The Decisive Decade 1864–1874 (Louvain, 1970), which contains much of Acton's correspondence for those years. Among other duties, Holland will be primarily responsible for the Index.

The object of the editors has been to reproduce both the text and the appearance of the letters as faithfully as is possible in print. Sometimes this is not entirely compatible with the conventions of publishing. For instance, Simpson had the bad habit of underlining his signature, sometimes twice or thrice, as a flourish. This can be accurately reproduced in typescript, but it appears in print in this volume as a single underline.

In all other respects, this volume is a continuation of Volume I. Where a person, book or article has been adequately footnoted in Volume I, the Index to this volume will indicate the location of that footnote.