Citation, Documentation of Sources

Q. How do you determine which publisher to cite if the book has had more than one publisher over time, and which publication date do you use: the latest edition/publication date, or when the book was first published?

A. Generally, cite the source you’ve consulted. Pagination and content may vary across different editions (or printings or postings) of the same work; citing an edition you did not consult could render your citation inaccurate. In any case, a full source citation to one edition of a work will generally be enough to lead readers to any other editions of a work. In some cases, especially for older or classic works, an original publication date is useful; it may be included, preferably in square brackets, before the date of the edition cited.

[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]