We have, however, in a few instances, repeated paragraphs, or in one or two cases whole letters, from the "Life and Letters," where such repetition seemed necessary for the sake of clearness or continuity.
Our two volumes contain practically all the matter that it now seems desirable to publish.

But at some future time others may find interesting data in what remains unprinted; this is certainly true of a short series of letters dealing with the Cirripedes, which are omitted solely for want of space.

(Preface/1.

Those addressed to the late Albany Hancock have already appeared in the "Transactions of the Tyneside Nat.
Field Club," VIII., page 250.) We are fortunate in being permitted, by Sir Joseph Hooker and by Mr.
Wallace, to publish certain letters from them to Mr.Darwin.We have also been able to give a few letters from Sir Charles Lyell, Hugh Falconer, Edward Forbes, Dr.Asa Gray, Professor Hyatt, Fritz Muller, Mr.Francis Galton, and Sir T.Lauder Brunton.

To the two last named, also to Mrs.Lyell (the biographer of Sir Charles), Mrs.Asa Gray and Mrs.Hyatt, we desire to express our grateful acknowledgments.
The present volumes have been prepared, so as to give as full an idea as possible of the course of Mr.Darwin's work.