Charles Lyell's Principles of Geology was published in 12 different editions between 1830 and 1875. The 1st and 2nd editions were issued in three volumes (of which Volume 3 was shared by both editions), the 3rd-5th editions in four volumes, the 6th edition in three volumes, the 7th-9th editions in one volume apiece, and the 10th-12th editions in two volumes.  The contents of Volume 2, and the portion of the book represented by it, thus varied considerably from edition to edition.

The publication history of Lyell's books is actually even more complicated than that description suggests. In the interest of simplicity, therefore, this LibraryThing "work" includes all copies of Principles of Geology, volume 2, regardless of edition. (In practice, most are probably 1st edition, which was issued as a facsimile reprint by the University of Chicago Press in the 1990s).

Please do not combine it with any other individual volume of Principles of Geology, with the complete work, or with the one-volume "Penguin Classics" abridgment edited by James Secord.